Terminal device, access network device, air interface configuration method, and wireless communications system

ABSTRACT

The present disclosure relates to terminal devices, access network devices, air interface configuration methods, and wireless communications systems. In one example method, a second access network device in a radio access network determines air interface configuration information of an air interface between a terminal device and the radio access network, and sends a first air interface configuration message comprising the air interface configuration information to a first access network device in the radio access network. The first access network device and the second access network device use different wireless communications standards.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/028,983, filed on Jul. 6, 2018, which is a continuation ofInternational Application No, PCT/CN2016/070498, filed on Jan. 8, 2016.The disclosure of all of the afore-mentioned patent applications arehereby incorporated by reference in their entirety.

TECHNICAL FIELD

This application relates to the field of wireless communicationstechnologies, and in particular, to a terminal device, an access networkdevice, an air interface configuration method, and a wirelesscommunications system.

BACKGROUND

As wireless communications technologies develop, various future evolvedwireless communications systems are emerging on the basis of a currentwireless communications system. A future evolved wireless communicationssystem may implement communication in a non-standalone working manner byusing another existing wireless communications system.

For example, as shown in FIG. 1, a terminal device accesses a basestation in a future evolved wireless communications system. The basestation is referred to as a future evolved base station for short. Thenthe terminal device accesses a core network in a long term evolution(LTE) system by using an LTE base station connected to the futureevolved base station.

A wireless communications system shown in FIG. 1 includes two parts: theterminal device and a network. The network includes a radio accessnetwork and a core network. There are two access network devices in theradio access network, and the two access network devices use differentwireless communications standards (for example, one is a future evolvedbase station, and the other is an LTE base station). The two accessnetwork devices implement wireless access of user equipment, and eachcompletes some processing in the radio access network. A current airinterface configuration method used when a terminal device accesses onlyone radio access network device is no longer applicable to the caseshown in FIG. 1.

SUMMARY

Embodiments of this application provide a terminal device, an accessnetwork device, an air interface configuration method, and a wirelesscommunications system, to successfully establish a connection between aterminal device and two radio access network devices of differentstandards when the terminal device needs to access a wirelesscommunications system by using the two access network devices.

According to a first aspect, an embodiment of this application providesan air interface configuration method, including:

determining, by a second access network device in a radio accessnetwork, air interface configuration information of an air interfacebetween a terminal device and the radio access network, and sending afirst air interface configuration message including the air interfaceconfiguration information to a first access network device in the radioaccess network, where the first access network device and the secondaccess network device use different wireless communications standards;sending, by the first access network device, the received first airinterface configuration message to the terminal device; and obtaining,by the terminal device, the air interface configuration information fromthe received first air interface configuration message, and configuringthe air interface between the terminal device and the radio accessnetwork according to the air interface configuration information.

The air interface between the terminal device and the radio accessnetwork includes a first air interface protocol layer and a second airinterface protocol layer. The first air interface protocol layer isbetween the terminal device and the first access network device, thesecond air interface protocol layer is between the terminal device andthe second access network device, and the second air interface protocollayer is above the first air interface protocol layer. The first airinterface configuration message is a message of an air interfaceprotocol layer that is in the second air interface protocol layer andthat is used to configure an air interface.

Based on a scenario in which there are two access network devices ofdifferent wireless communications standards in the radio access networkand the two access network devices jointly provide a complete airinterface protocol stack to the terminal device the foregoing methodprovides a method for configuring the air interface between the terminaldevice and the radio access network.

The first air interface configuration message is a message of the secondair interface protocol layer existing only between the terminal deviceand the second access network device, and no second air interfaceprotocol layer exists between the terminal device and the first accessnetwork device. Therefore, an air interface needs to be configured forthe terminal device by sending a message to the terminal device by thesecond access network device.

In an optional implementation solution, after determining the airinterface configuration information, the second access network devicesends a second air interface configuration message to the first accessnetwork device, where the second air interface configuration messageincludes configuration information of the first air interface protocollayer in the air interface configuration information; and the firstaccess network device configures the first air interface protocol layeraccording to the configuration information of the first air interfaceprotocol layer in the received second air interface configurationmessage.

The second access network device sends the second air interfaceconfiguration message to the first access network device, so that thefirst access network device configures the first air interface protocollayer between the first access network device and the terminal device,and configuration information of the first air interface protocol layerreceived by the terminal device is the same as that received by thefirst access network device. This ensures communication between the twodevices at the first air interface protocol layer.

In another optional implementation solution, the first access networkdevice determines configuration information of the first air interfaceprotocol layer, adds the determined configuration information of thefirst air interface protocol layer to a third air interfaceconfiguration message, and sends the third air interface configurationmessage to the second access network device; the second access networkdevice obtains the configuration information of the first air interfaceprotocol layer from the received third air interface configurationmessage, adds, to the first air interface configuration message, theconfiguration information of the first air interface protocol layerobtained from the third air interface configuration message, and sendsthe first air interface configuration message to the terminal device.

The first access network device determines the configuration informationof the first air interface protocol layer between the first accessnetwork device and the terminal device, and sends the configurationinformation to the second access network device, and the second accessnetwork device then sends the received configuration information of thefirst air interface protocol layer to the terminal device by using thefirst air interface configuration message. In this way, the first accessnetwork device can configure the first air interface protocol layerbetween first access network device and the terminal device.

Further, if the first access network device determines the configurationinformation of the first air interface protocol layer, adds thedetermined configuration information of the first air interface protocollayer to the third air interface configuration message, and sends thethird air interface configuration message to the second access networkdevice, the first access network device further performs configurationaccording to the determined configuration information of the first airinterface protocol layer, and configuration information of the first airinterface protocol layer received by the terminal device is the same asthe configuration information used when the first access network deviceperforms configuration. This ensures communication between the twodevices at the first air interface protocol layer.

With reference to the first aspect or either of the foregoing optionalimplementation solutions of the first aspect, in an optionalimplementation solution, a second wireless communications system is along term evolution (LTE) system, and a first wireless communicationssystem is a 5G system.

According to a second aspect, an embodiment of this application providesa second access network device. The second access network device has afunction of implementing operations of the second access network devicein the foregoing method. The function may be implemented by usinghardware, or may be implemented by hardware executing correspondingsoftware. The hardware or software includes one or more modulescorresponding to the foregoing function.

In an optional implementation solution, a structure of the second accessnetwork device includes a processor and a transmitter. The processor isconfigured to support the second access network device in implementingcorresponding functions in the foregoing method. The transmitter isconfigured to support the second access network device in sending, to afirst access network device, a message or data included in the foregoingmethod. Optionally, the second access network device may further includea receiver, configured to receive, from the first access network device,a message or data included in the foregoing method. The second accessnetwork device may further include a memory. The memory is configured tobe coupled with the processor, and the memory stores a programinstruction and data necessary for the second access network device.

According to a third aspect, an embodiment of this application providesa first access network device. The first access network device has afunction of implementing operations of the first access network devicein the foregoing method. The function may be implemented by usinghardware, or may be implemented by hardware executing correspondingsoftware. The hardware or software includes one or more modulescorresponding to the foregoing function.

In an optional implementation solution, a stricture of the first accessnetwork device includes a receiver, configured to support the firstaccess network device in receiving, from a second access network device,a message or data included in the foregoing method; and a firsttransmitter, configured to support the first access network device insending, to a terminal device, a message or data included in theforegoing method. Optionally, the first access network device furtherincludes a processor, configured to support the second access networkdevice in implementing corresponding functions in the foregoing method.The first access network device may further include a memory. The memoryis configured to be coupled with the processor, and the memory stores aprogram instruction and data necessary for the first access networkdevice.

According to a fourth aspect, an embodiment of this application providesa terminal device. The terminal device has a function of implementingoperations of the terminal device in the foregoing method. The functionmay be implemented by using hardware, or may be implemented by hardwareexecuting corresponding software. The hardware or software includes oneor more modules corresponding to the foregoing function.

In an optional implementation solution, a structure of the terminaldevice includes a receiver, configured to support the terminal device inreceiving, from a first access network device, a message or dataincluded in the foregoing method; and a processor, configured to supportthe terminal device in implementing corresponding functions in theforegoing method. Optionally, the terminal device further includes amemory, the memory is configured to be coupled with the processor, andthe memory stores a program instruction and data necessary for theterminal device.

According to a fifth aspect, an embodiment of this application providesa wireless communications system. The wireless communications systemincludes the terminal device, the first access network device, and thesecond access network device according to any one of the first to thefourth aspects.

According to a sixth aspect, an embodiment of this application providesa computer storage medium, configured to store a computer softwareinstruction used by the second access network device according to anyone of the first to the fifth aspects. The computer software instructionincludes programs designed for executing the foregoing aspects.

According to a seventh aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the first access network device accordingto any one of the first to the fifth aspects. The computer softwareinstruction includes programs designed for executing the foregoingaspects.

According to an eighth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the terminal device according to any one ofthe first to the fifth aspects. The computer software instructionincludes programs designed for executing the foregoing aspects.

According to a ninth aspect, an embodiment of this application providesan air interface configuration method, including: determining, by asecond access network device in a radio access network, air interfaceconfiguration information of an air interface between a terminal deviceand the radio access network, adding the determined air interfaceconfiguration information to a first air interface configurationmessage, and sending the first air interface configuration message to afirst access network device in the radio access network; sending, by thefirst access network device, the received first air interfaceconfiguration message to the terminal device; and obtaining, by theterminal device, the air interface configuration information from thefirst air interface configuration message, and configuring an airinterface between the terminal device and the radio access networkaccording to the air interface configuration information, where

the air interface between the terminal device and the radio accessnetwork includes a first air interface and a second air interface; thefirst air interface includes a first air interface protocol layer and asecond air interface protocol layer, the first air interface protocollayer is between the terminal device and the first access networkdevice, the second air interface protocol layer is between the terminaldevice and the second access network device, and the second airinterface protocol layer is above the first air interface protocollayer; the second air interface is an air interface between the terminaldevice and the second access network device; and the first air interfaceconfiguration message is a message of an air interface protocol layerthat is included in the second air interface and that is used toconfigure an air interface.

Based on a scenario in which there are two access network devices ofdifferent wireless communications standards in the radio access network,the two access network devices jointly provide a complete air interfaceprotocol stack to the terminal device over an air interface between theterminal device and the first access network device, and the secondaccess network device also provides another complete set of airinterface protocol stack to the terminal device, the foregoing methodprovides a method for configuring the air interface between the terminaldevice and the radio access network. The first air interfaceconfiguration message is the message of the air interface protocol layerthat is included in the second air interface between the terminal deviceand the second access network device and that is used to configure anair interface. This achieves an objective of configuring the first airinterface and the second air interface by using the second accessnetwork device.

In addition, the terminal device not only establishes an air interfaceconnection to the first access network device, but also establishes anair interface connection to the second access network device. In thiscase, when the terminal device moves from a coverage area of a cellmanaged by the first access network device to a coverage area of a cellmanaged by the second access network device, there is no need toestablish an air interface connection any further. This can implement aquick and seamless handover.

In an optional implementation solution, the second air interfaceincludes a third air interface protocol layer and a fourth air interfaceprotocol layer, the fourth air interface protocol layer is above thethird air interface protocol layer, and the fourth air interfaceprotocol layer and the second air interface protocol layer include asame type of protocol layer;

the first air interface configuration message is a message of an airinterface protocol layer that is in the fourth air interface protocollayer and that is used to configure an air interface; and

the fourth air interface protocol layer and the second air interfaceprotocol layer are a same air interface protocol layer; or the fourthair interface protocol layer and the second air interface protocol layerare independent from each other.

In an optional implementation solution, after determining the airinterface configuration information, the second access network devicesends a second air interface configuration message to the first accessnetwork device, where the second air interface configuration messageincludes configuration information of the first air interface protocollayer in the air interface configuration information.

The first access network device receives the second air interfaceconfiguration message from the second access network device, where thesecond air interface configuration message includes the configurationinformation of the first air interface protocol layer in the airinterface configuration information. The first access network deviceconfigures the first air interface protocol layer according to theconfiguration information of the first air interface protocol layer inthe received second air interface configuration message.

The second access network device sends the second air interfaceconfiguration message to the first access network device, so that thefirst access network device configures the first air interface protocollayer between the first access network device and the terminal device,and configuration information of the first air interface protocol layerreceived by the terminal device is the same as that received by thefirst access network device. This ensures communication between the twodevices at the first air interface protocol layer.

In another optional implementation solution, the first access networkdevice determines configuration information of the first air interfaceprotocol layer, adds the determined configuration information of thefirst air interface protocol layer to a third air interfaceconfiguration message, and sends the third air interface configurationmessage to the second access network device; and the second accessnetwork device adds, to the first air interface configuration message,the configuration information of the first air interface protocol layerreceived from the first access network device, and sends the first airinterface configuration message to the terminal device.

The first access network device determines the configuration informationof the first air interface protocol layer between the first accessnetwork device and the terminal device, and sends the configurationinformation to the second access network device, and the second accessnetwork device then sends the received configuration information of thefirst air interface protocol layer to the terminal device by using thefirst air interface configuration message. In this way, the first accessnetwork device can configure the first air interface protocol layerbetween first access network device and the terminal device.

Further, if the first access network device determines the configurationinformation of the first air interface protocol layer, and sends thedetermined configuration information of the first air interface protocollayer to the second access network device, the first access networkdevice further performs configuration according to the determinedconfiguration information of the first air interface protocol layer, andconfiguration information of the first air interface protocol layerreceived by the terminal device is the same as the configurationinformation used when the first access network device performsconfiguration. This ensures communication between the two devices at thefirst air interface protocol layer.

With reference to the ninth aspect or either of the foregoing optionalimplementation solutions of the ninth aspect, in an optionalimplementation solution, a second wireless communications system is aLong Term Evolution (LTE) system, and a first wireless communicationssystem is a 5^(th) Generation 5G system.

According to a tenth aspect, an embodiment of this application providesa second access network device, where the second access network devicehas a function of implementing operations of the second access networkdevice in the foregoing method. The function may be implemented by usinghardware, or may be implemented by hardware executing correspondingsoftware. The hardware or software includes one or more modulescorresponding to the foregoing function.

In an optional implementation solution, a structure of the second accessnetwork device includes a processor and a transmitter. The processor isconfigured to support the second access network device in implementingcorresponding functions in the foregoing method. The transmitter isconfigured to support the second access network device in sending, to afirst access network device, a message or data included in the foregoingmethod. Optionally, the second access network device may further includea receiver, configured to receive, from the first access network device,a message or data included in the foregoing method. The second accessnetwork device may further include a memory. The memory is configured tobe coupled with the processor, and the memory stores a programinstruction and data necessary for the second access network device.

According to an eleventh aspect, an embodiment of this applicationprovides a first access network device, where the first access networkdevice has a function of implementing operations of the first accessnetwork device in the foregoing method. The function may be implementedby using hardware, or may be implemented by hardware executingcorresponding software. The hardware or software includes one or moremodules corresponding to the foregoing function.

In an optional implementation solution, a structure of the first accessnetwork device includes a receiver, configured to support the firstaccess network device in receiving, from a second access network device,a message or data included in the foregoing method; and a firsttransmitter, configured to support the first access network device insending, to a terminal device, a message or data included in theforegoing method. Optionally, the first access network device furtherincludes a processor, configured to support the second access networkdevice in implementing corresponding functions in the foregoing method.The first access network device may further include a memory. The memoryis configured to be coupled with the processor, and the memory stores aprogram instruction and data necessary for the first access networkdevice.

According to a twelfth aspect, an embodiment of this applicationprovides a terminal device. The terminal device has a function ofimplementing operations of the terminal device in the foregoing method.The function may be implemented by using hardware, or may be implementedby hardware executing corresponding software. The hardware or softwareincludes one or more modules corresponding to the foregoing function.

In an optional implementation solution, a structure of the terminaldevice includes a receiver, configured to support the terminal device inreceiving, from a first access network device, a message or dataincluded in the foregoing method; and a processor, configured to supportthe terminal device in implementing corresponding functions in theforegoing method. Optionally, the terminal device further includes amemory, the memory is configured to be coupled with the processor, andthe memory stores a program instruction and data necessary for theterminal device.

According to a thirteenth aspect, an embodiment of this applicationprovides a wireless communications system. The wireless communicationssystem includes the terminal device, the first access network device,and the second access network device according to any one of the ninthto the twelfth aspects.

According to a fourteenth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the second access network device accordingto any one of the ninth to the thirteenth aspects. The computer softwareinstruction includes programs designed for executing the foregoingaspects.

According to a fifteenth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the first access network device accordingto any one of the ninth to the thirteenth aspects. The computer softwareinstruction includes programs designed for executing the foregoingaspects.

According to a sixteenth aspect, an embodiment of this applicationprovides a computer storage medium, configured to store a computersoftware instruction used by the terminal device according to any one ofthe ninth to the thirteenth aspects. The computer software instructionincludes programs designed for executing the foregoing aspects.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a network architecture diagram of a wireless communicationssystem;

FIG. 2A and FIG. 2B are schematic diagrams of two structures of awireless communications system according to an embodiment of thisapplication;

FIG. 3A to FIG. 3D are schematic structural diagrams of air interfaceprotocol stacks used when a wireless communications system uses astructure shown in FIG. 2A according to an embodiment of thisapplication;

FIG. 4A to FIG. 4D are schematic structural diagrams of air interfaceprotocol stacks used when a wireless communications system uses astructure shown in FIG. 2B according to an embodiment of thisapplication;

FIG. 5A to FIG. 5D are schematic diagrams of user plane and controlplane based transmission performed when a wireless communications systemuses a structure shown in FIG. 2A according to an embodiment of thisapplication;

FIG. 6A to FIG. 6D are schematic diagrams of user plane and controlplane based transmission performed when a wireless communications systemuses a structure shown in FIG. 2B according to an embodiment of thisapplication;

FIG. 7 is a schematic diagram of an air interface configurationprocedure according to Embodiment 1 of this application;

FIG. 8 is a schematic diagram of an air interface configurationprocedure according to Embodiment 2 of this application;

FIG. 9 is a schematic diagram of an air interface configurationprocedure according to Embodiment 3 of this application;

FIG. 10 is a schematic diagram of an air interface configurationprocedure according to Embodiment 4 of this application;

FIG. 11 is a schematic structural diagram of a second access networkdevice according to Embodiment 5;

FIG. 12 is a schematic structural diagram of an optional implementationof the second access network device provided in Embodiment 5;

FIG. 13 is a schematic structural diagram of a first access networkdevice according to Embodiment 6;

FIG. 14 is a schematic structural diagram of an optional implementationof the first access network device provided in Embodiment 6;

FIG. 15 is a schematic structural diagram of a terminal device accordingto Embodiment 7;

FIG. 16 is a schematic structural diagram of an optional implementationof the terminal device provided in Embodiment 7;

FIG. 17 is a schematic structural diagram of a second access networkdevice according to Embodiment 8;

FIG. 18 is a schematic structural diagram of an optional implementationof the second access network device provided in Embodiment 8;

FIG. 19 is a schematic structural diagram of a first access networkdevice according to Embodiment 9;

FIG. 20 is a schematic structural diagram of an optional implementationof the first access network device provided in Embodiment 9;

FIG. 21 is a schematic structural diagram of a terminal device accordingto Embodiment 10; and

FIG. 22 is a schematic structural diagram of an optional implementationof the terminal device provided in Embodiment 10.

DESCRIPTION OF EMBODIMENTS

To make the objectives, solutions, and advantages of the embodiments ofthis application more understandable, the following provides detaileddescriptions. The detailed descriptions provide various implementationsof an apparatus and/or a method by using block diagrams, flowcharts,other accompany drawings, and/or examples. These block diagrams,flowcharts, and/or examples include one or more functions and/oroperations. Persons skilled in the art may understand that each functionand/or operation in the block diagrams, the flowcharts, and/or theexamples can be performed independently or jointly by using varioustypes of hardware, software, and firmware, or any combination thereof.

The following explains some description of the embodiments of thisapplication. It should be noted that, these explanations are intended tomake the embodiments of this application more understandable, and shouldnot be considered as a limitation on the protection scope required bythe embodiments of this application.

1. Structure of a wireless communications system to which theembodiments of this application are applicable:

The embodiments of this application provide a wireless communicationssystem, including:

a terminal device 201, a first access network device 202, and a secondaccess network device 203. The first access network device 202 and thesecond access network device 203 use different wireless communicationsstandards. A connection has been established between the devices.

The wireless communications system may further include a core network.The core network is connected to the second access network device 203.

One case is shown in FIG. 2A:

The terminal device 201 establishes an air interface connection only tothe first access network device 202. The terminal device 201 may beconnected to the core network by using the first access network device202 and the second access network device 203.

Another case is shown in FIG. 2B:

The terminal device 201 not only establishes an air interface connectionto the first access network device 202, but also establishes an airinterface connection to the second access network device 203. Herein, anair interface between the terminal device 201 and the first accessnetwork device 202 is referred to as a “first air interface”, and an airinterface between the terminal device 201 and the second access networkdevice 203 is referred to as a “second air interface”. The terminaldevice 201 is connected to the core network by using the second accessnetwork device 203.

Herein, the first access network device 202 and the second accessnetwork device 203 are devices in a radio access network. For example,the device may be a base station or a base station controller configuredto control a base station, or may include a base station and a basestation controller. For example, the first access network device 202 maybe the aforementioned future evolved base station, for example, a 5^(th)generation (5G) base station, and the second access network device 203may be a base station in a current wireless communications system.

A wireless communications standard of the second access network device203 may include but not limited to: the global system for mobilecommunications (GSM), code division multiple access (CDMA) IS-95, codedivision multiple access (CDMA) 2000, time division-synchronous codedivision multiple access (TD-SCDMA), wideband code division multipleaccess (WCDMA), time division duplex-long term evolution (TDD LTE),frequency division duplex-long term evolution (FDD LTE), long termevolution-advanced (LTE-advanced), the personal handy-phone system(PHS), wireless fidelity (WiFi) stipulated in the 802.11 series ofprotocols, worldwide interoperability for microwave access (WiMAX), andvarious future evolved wireless communications systems.

The terminal device 201 may be a wireless terminal. The wirelessterminal may be a device providing voice and/or data connectivity to auser, a handheld device having a wireless connection function, oranother processing device connected to a wireless modem. The wirelessterminal may communicate with one or more core networks by using a radioaccess network (RAN). The wireless terminal may be a mobile terminal,such as a mobile phone (also referred to as a “cellular” phone) or acomputer having a mobile terminal. For example, the mobile terminal maybe a portable mobile apparatus, a pocket-sized mobile apparatus, ahandheld mobile apparatus, a computer built-in mobile apparatus, or anin-vehicle mobile apparatus. They exchange voice and/or data with theradio access network. For example, the wireless terminal is a personalcommunications service (PCS) phone, a cordless phone, a SessionInitiation Protocol (SIP) phone, a wireless local loop (WLL) station, apersonal digital assistant (PDA), or another device. The wirelessterminal may alternatively be referred to as a subscriber unit, asubscriber station, a mobile station, a remote station, an access point,a remote terminal, an access terminal, a user terminal, a user agent, auser device, or user equipment.

In the case shown in FIG. 2A, the terminal device 201 establishes an airinterface connection to the first access network device 202, andtherefore, the terminal device 201 needs to support an air interfaceprotocol used between the terminal device 201 and the first accessnetwork device 202. In addition, the terminal device 201 may need to beconnected to the core network by using the second access network device203, and when communicating with the second access network device 203,the terminal device 201 needs to support a communications protocol usedwhen the terminal device 201 communicates with the second access networkdevice 203. In addition, the terminal device 201 needs to be connectedto the core network, and therefore, the terminal device 201 needs tosupport a communications protocol used when the terminal device 201communicates with the core network.

In the case shown in FIG. 2B, the terminal device 201 establishes an airinterface connection to the first access network device 202, and alsoestablishes an air interface connection to the second access networkdevice 203, and therefore, the terminal device 201 needs to support bothan air interface protocol used between the terminal device 201 and thefirst access network device 202 and an air interface protocol usedbetween the terminal device 201 and the second access network device203. In addition, if the terminal device 201 needs to be connected tothe core network, the terminal device 201 needs to support acommunications protocol used when the terminal device 201 communicateswith the core network.

The first access network device 202 and the second access network device203 may include a base station or a radio resource management deviceconfigured to control a base station, or may include a base station anda radio resource management device configured to control a base station.The base station may be a macro base station or a small cell, forexample, a small cell or a pico cell. The base station may alternativelybe a home base station, for example, a home nodeB (HNB) or a homeevolved nodeB (HeNB). The base station may alternatively include a relaynode or the like.

2. Air interface protocol stack existing between the terminal device 201and the first access network device 202 and the second access networkdevice 203

In the embodiments of this application, there is no complete airinterface protocol stack between the terminal device 201 and the firstaccess network device 202. For example, only a layer 1 and a layer 2 areincluded, or only a layer 1 is included.

The following uses an example in which the first access network device202 is a 5G base station and the second access network device 203 is anLTE base station for description.

1. In the Case Shown in FIG. 2A

The first access network device 202 and the second access network device203 jointly provide a complete air interface protocol stack to theterminal device 201. There are the following three possibleimplementations.

Manner 1:

There is only a physical (PHY) layer, a media access control (MAC)layer, and a radio link control (RLC) layer between the first accessnetwork device 202 and the terminal device 201.

There is a packet data convergence protocol (PDCP) layer between theterminal device 201 and the second access network device 203. On acontrol plane (CP), there is a radio resource control (RRC) layer abovethe PDCP layer. On a user plane (UP), there is an internet protocol (IP)layer above the PDCP layer.

When Manner 1 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 3A.

When Manner 1 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 5A.

When Manner 1 is used, the terminal device 201 may perform access byusing the first access network device 202 in a dual connectivity (DC)manner. An anchor of the user plane and an anchor of the control planeare at the PDCP layer of the second access network device 203.

Manner 2:

There is only a PHY layer and a MAC layer between the first accessnetwork device 202 and the terminal device 201.

There is an RLC layer and a PDCP layer between the terminal device 201and the second access network device 203. On a control plane, there is aradio resource control RRC layer above the PDCP layer. On a user plane,there is an IP layer above the PDCP layer.

When Manner 2 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 3B.

When Manner 2 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 5B.

When Manner 2 is used, the terminal device 201 may perform access byusing the first access network device 202 in a DC manner. An anchor ofthe user plane and an anchor of the control plane are at the RLC layerof the second access network device 203.

Manner 3:

There is only a PHY layer and a part of a MAC layer between the firstaccess network device 202 and the terminal device 201. The part of theMAC layer may be referred to as a “first MAC sublayer”.

There is the other part of the MAC layer between the terminal device 201and the second access network device 203. The other part of the MAClayer may be referred to as a “second MAC sublayer”. An RLC layer and aPDCP layer are further included. On a control plane, there is a radioresource control RRC layer above the PDCP layer. On a user plane, thereis an IP layer above the PDCP layer.

The first MAC sublayer may be used to implement a function, such asadding a MAC header. The second MAC sublayer may be used to implement afunction, such as scheduling.

When Manner 3 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 3C.

When Manner 3 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 5C.

When Manner 3 is used, the terminal device 201 may perform access byusing the first access network device 202 in a carrier aggregation (CA)manner. An anchor of the user plane and an anchor of the control planeare at the second MAC sublayer of the second access network device 203.

Manner 4:

There is only a PHY layer between the first access network device 202and the terminal device 201.

There is a MAC layer, an RLC layer, and a PDCP layer between theterminal device 201 and the second access network device 203. On acontrol plane, there is a radio resource control RRC layer above thePDCP layer. On a user plane, there is an IP layer above the PDCP layer.

When Manner 4 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 3D.

When Manner 4 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 5D.

When Manner 4 is used, the terminal device 201 may perform access byusing the first access network device 202 in a CA manner. An anchor ofthe user plane and an anchor of the control plane are at the MAC layerof the second access network device 203.

In conclusion, in the foregoing four possible implementations, an airinterface protocol layer between the first access network device 202 andthe terminal device 201 is referred to as a “first air interfaceprotocol layer”, and an air interface protocol layer between theterminal device 201 and the second access network device 203 is referredto as a “second air interface protocol layer”. The second air interfaceprotocol layer is above the first air interface protocol layer, andexists only between the terminal device 201 and the second accessnetwork device 203.

The second air interface protocol layer includes an air interfaceprotocol layer used to configure an air interface. For example, when thesecond access network device 203 is an LW base station, the airinterface protocol layer used to configure an air interface may be anRRC layer.

2. In the Case Shown in FIG. 2B

There is an air interface connection between the terminal device 201 andthe first access network device 202, and there is also an air interfaceconnection between the terminal device 201 and the second access networkdevice 203.

Herein, an air interface between the terminal device 201 and the firstaccess network device 202 is referred to as a “first air interface”, andan air interface between the terminal device 201 and the second accessnetwork device 203 is referred to as a “second air interface”.

On the first air interface, the first access network device 202, and thesecond access network device 203 jointly provide a complete airinterface protocol stack to the terminal device 201.

Possible implementations of an air interface protocol stack existingbetween the terminal device 201 and the first access network device 202and the second access network device 203 may be divided into thefollowing four manners according to possible different implementationsof the first air interface. Certainly, another manner may exist,provided that communication between the terminal device 201 and thefirst access network device 202 and the second access network device 203can be implemented.

Manner 1:

On the first air interface, there is only a PHY layer, a MAC layer, andan RLC layer between the first access network device 202 and theterminal device 201.

On the first air interface, there is a PDCP layer between the terminaldevice 201 and the second access network device 203. On a control plane,there is an RRC layer above the PDCP layer. On a user plane, there is anIP layer above the PDCP layer.

On the second air interface, there is a complete air interface protocolstack between the terminal device 201 and the second access networkdevice 203. For example, the second access network device 203 is an LTEbase station. There is a PHY layer, a MAC layer, an RLC layer, and aPDCP layer between the terminal device 201 and the second access networkdevice 203. On a control plane, there is an RRC layer above the PDCPlayer. On a user plane, there is an IP layer above the PDCP layer.

When Manner 1 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 4A.

When Manner 1 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 6A.

When Manner 1 is used, on the first air interface, the terminal device201 may perform access by using the first access network device 202 in aDC manner. An anchor of the user plane and an anchor of the controlplane are at the PDCP layer of the second access network device 203.

Manner 2:

On the first air interface, there is only a PHY layer and a MAC layerbetween the first access network device 202 and the terminal device 201.

On the first air interface, there is an RLC layer and a PDCP layerbetween the terminal device 201 and the second access network device203. On a control plane, there is an RRC layer above the PDCP layer. Ona user plane, there is an IP layer above the PDCP layer.

On the second air interface, there is a complete air interface protocolstack between the terminal device 201 and the second access networkdevice 203. For example, the second access network device 203 is an LTEbase station. There is a PHY layer, a MAC layer, an RLC layer, and aPDCP layer between the terminal device 201 and the second access networkdevice 203. On a control plane, there is an RRC layer above the PDCPlayer. On a user plane, there is an IP layer above the PDCP layer.

When Manner 2 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 4B.

When Manner 2 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 6B.

When Manner 2 is used, on the first air interface, the terminal device201 may perform access by using the first access network device 202 in aDC manner. An anchor of the user plane and an anchor of the controlplane are at the RLC layer of the second access network device 203.

Manner 3:

On the first air interface, there is only a PEW layer and a part of aMAC layer between the first access network device 202 and the terminaldevice 201. The part of the MAC layer may be referred to as a “third MACsublayer”.

On the first air interface, there is the other part of the MAC layerbetween the terminal device 201 and the second access network device203. The other part of the MAC layer may be referred to as a “fourth MACsublayer”. An RLC layer and a PDCP layer are further included. On acontrol plane, there is a radio resource control RRC layer above thePDCP layer. On a user plane, there is an IP layer above the PDCP layer.

The third MAC sublayer may be used to implement a function, such asadding a MAC header. The fourth MAC sublayer may be used to implement afunction, such as scheduling.

On the second air interface, there is a complete air interface protocolstack between the terminal device 201 and the second access networkdevice 203. For example, the second access network device 203 is an LTEbase station. There is a PHY layer, a MAC layer, an RLC layer, and aPDCP layer between the terminal device 201 and the second access networkdevice 203. On a control plane, there is an RRC layer above the PDCPlayer. On a user plane, there is an IP layer above the PDCP layer. Onthe second air interface, the MAC layer may alternatively not be dividedinto a fourth MAC sublayer and a third MAC sublayer.

When Manner 3 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 4C.

When Manner 3 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 6C.

When Manner 3 is used, on the first air interface, the terminal device201 may perform access by using the first access network device 202 in aCA manner. An anchor of the user plane and an anchor of the controlplane are at the fourth MAC sublayer of the second access network device203.

Manner 4:

On the first air interface, there is only a PHS layer between the firstaccess network device 202 and the terminal device 201.

On the first air interface, there is a MAC layer, an RLC layer, and aPDCP layer between the terminal device 201 and the second access networkdevice 203. On a control plane, there is an RRC layer above the PDCPlayer. On a user plane, there is an IP layer above the PDCP layer.

On the second air interface, there is a complete air interface protocolstack between the terminal device 201 and the second access networkdevice 203. For example, the second access network device 203 is an LTEbase station. There is a my layer, a MAC layer, an RLC layer, and a PDCPlayer between the terminal device 201 and the second access networkdevice 203. On a control plane, there is an RRC layer above the PDCPlayer. On a user plane, there is an IP layer above the PDCP layer.

When Manner 4 is used, a structure of a protocol stack existing betweenthe terminal device 201 and the first access network device 202 and thesecond access network device 203 is shown in FIG. 4D.

When Manner 4 is used, user plane based data transmission and controlplane based signaling transmission may be shown in FIG. 6D.

When Manner 4 is used, on the first air interface, the terminal device201 may perform access by using the first access network device 202 in aCA manner. An anchor of the user plane and an anchor of the controlplane are at the MAC layer of the second access network device 203.

In conclusion, in the foregoing four possible implementations:

On the first air interface, an air interface protocol layer between thefirst access network device 202 and the terminal device 201 is referredto as a “first air interface protocol layer”, and an air interfaceprotocol layer between the terminal device 201 and the second accessnetwork device 203 is referred to as a “second air interface protocollayer”. The second air interface protocol layer is above the first airinterface protocol layer, and exists only between the terminal device201 and the second access network device 203.

The second air interface protocol layer includes an air interfaceprotocol layer used to configure an air interface. For example, when thesecond access network device 203 is an LW base station, the airinterface protocol layer used to configure an air interface may be anRRC layer.

On the second air interface, a protocol stack included in the second airinterface may be divided into a third air interface protocol layer and afourth air interface protocol layer. The fourth air interface protocollayer is above the third air interface protocol layer. The fourth airinterface protocol layer and the second air interface protocol layerinclude a same type of protocol layer. The fourth air interface protocollayer and the second air interface protocol layer are a same airinterface protocol layer (FIG. 6A to FIG. 6D show cases in which thefirst air interface protocol layer and the second air interface protocollayer are a same air interface protocol layer). Alternatively, thefourth air interface protocol layer and the second air interfaceprotocol layer are independent from each other.

3. Optional Manner for Air Interface Configuration

An objective of air interface configuration is to establish an airinterface connection between a terminal device and an access networkdevice, and the terminal device and the access network device cantransmit signaling and data through the established air interfaceconnection.

Optionally, in the embodiments of this application, an air interfaceconfiguration procedure in a current LTE system may be used: A controlplane is first configured, and then, a user plane is configured.

On an air interface, signaling may be transmitted by using a signalingradio bearer (SRB), and data may be transmitted by using a data radiobearer (DRB).

Therefore, in an air interface configuration procedure, when an SRB anda DRB are configured, it may be considered that air interfaceconfiguration is completed.

1. Control Plane Establishment

According to definitions of an SRB and a DRB in the current LTE system,an SRB may be divided into an SRB 0, an SRB 1, and an SRB 2 according totransmission signaling content:

The SRB 0 may be used to transmit a request message, for example, an RRCconnection request message used in the LTE system, that is sent by theterminal device 201 for requesting to establish an air interfaceconnection.

The SRB 1 may be used to transmit a subsequent RRC message, and beforean SRB 2 is established, transmit a non-access stratum (NAS) message.When an RRC connection is set up, it indicates that an SRB 1 linkbetween the terminal device 201 and the first access network device 202and the second access network device 203 is established, and then, theSRB 1 may be used to transmit an RRC message.

In the embodiments of this application, there is no RRC layer betweenthe terminal device 201 and the first access network device 202.Therefore, the RRC message is transmitted between UE and the secondaccess network device 203 after being processed by the first airinterface protocol layer of the first access network device 202.

After receiving an RRC connection request message from the terminaldevice 201, if an RRC connection is allowed to be set up, the secondaccess network device 203 sends an RRC connection setup message to theterminal device 201. The message includes configuration information usedto configure an SRB 1. For example, the configuration information is:

an SRB identity (ID), RLC configuration information, and logical channel(LCH) configuration information.

The SRB 2 is used to transmit an NAS message. After the SRB 1 issuccessfully established, and after security is activated, an SRB 2 linkmay be established.

2. User Plane Establishment

In the embodiments of this application, a procedure in the LTE systemmay be used. After receiving an RRC connection setup message, theterminal device 201 returns an RRC connection setup complete message tothe second access network device 203.

Then, the second access network device 203 may add an NAS message, forexample, a service request message to an initial UE message that is tobe sent to a core network, for example, a mobility management entity(MME). The core network may send an initial context setup requestmessage to the second access network device 203. The initial contextsetup request message includes information required for configuring aDRB for the terminal device 201 by the second access network device 203,for example, a user equipment aggregate maximum bit rate (UE AMBR), anevolved universal terrestrial radio access network radio access bearerE-RAB), or quality of service (QoS).

After receiving the initial context setup request message from the corenetwork, the second access network device 203 sends an RRC connectionreconfiguration message to the terminal device 201 according to theinformation, required for configuring a DRB, that is included in theinitial context setup request message. The RRC connectionreconfiguration message includes DRB configuration information.

The DRB configuration information mainly includes an evolved packetsystem (EPS) bearer ID, a DRB ID, PDCP configuration information, RLCconfiguration information, an LCH ID, LCH configuration information, andthe like.

For the foregoing configuration manners and procedures of the controlplane and the user plane, reference has been made to the procedure inthe current LTE system. Actually, in the embodiments of thisapplication, another configuration manner may be used, provided thateach air interface protocol layer can be configured for transmittingdata and signaling and completing communication.

In a transmission process of the foregoing configuration message, in thecase shown in FIG. 2A, a configuration message of an air interfaceconnection between the terminal device 201 and the first access networkdevice 202 needs to be forwarded by the first access network device 202.There is no complete air interface protocol stack between the terminaldevice 201 and the first access network device 202. Therefore, theconfiguration message needs to be parsed by the air interface protocollayer that is in the second air interface protocol layer between thesecond access network device 203 and the terminal device 201 and that isused to configure an air interface.

In a transmission process of the foregoing configuration message, in thecase shown in FIG. 2B, a configuration message of the first airinterface between the terminal device 201 and the first access networkdevice 202 may be forwarded by the first access network device 202, andparsed and processed by the air interface protocol layer that is in thesecond air interface protocol layer between the second access networkdevice 203 and the terminal device 201 and that is used to configure anair interface. Alternatively, the configuration message may not beforwarded by the first access network device 202, but directlytransmitted over the second air interface between the terminal device201 and the second access network device 203, and parsed and processedby an air interface protocol layer that is in the fourth air interfaceprotocol layer between the terminal device 201 and the second accessnetwork device 203 and that is used to configure an air interface.

4. Establishment of a Connection Between the First Access Network Device202 and the Second Access Network Device 203

To implement transmission of a message related to air interfaceconfiguration, in the embodiments of this application, a connectionbetween the first access network device 202 and the second accessnetwork device 203 needs to be established.

For example, the first access network device 202 is a 5^(th) generation(5G) base station, and the second access network device 203 is an LTEbase station. An interface is pre-established between the 5G basestation and the LTE base station, and may be referred to as an “X5interface”.

For example, the 5G base station learns of a transport network layer(TNL) addressing address of the LTE base station by using an operation,administration, and maintenance (OAM) configuration, and then initiatesa request for establishing an X5 interface. Alternatively, the LTE basestation learns of a TNL addressing address of the 5G base station byusing an OAM configuration, and then initiates a request forestablishing an X5 interface. The 5G base station and the LTE basestation may exchange cell load, a data transmission delay, a backhaullink capacity, or other information with each other by using the X5interface.

The foregoing explains some description of the embodiments of thisapplication. The following provides illustrative descriptions by usingspecific embodiments.

In both the case shown in FIG. 2A and the case of the first airinterface shown in FIG. 2B, the first access network device 202 and thesecond access network device 203 need to jointly provide a complete airinterface protocol stack to the terminal device 201, and the firstaccess network device 202 cannot provide a complete air interfaceprotocol stack to the terminal device 201. The following Embodiment 1and Embodiment 2 provide a solution in which the first access networkdevice 202 and the second access network device 203 jointly provide acomplete air interface protocol stack to the terminal device 201.

In addition, if the terminal device 201 performs access only by usingthe first access network device 202, and there is no air interfaceconnection between the terminal device 201 and the second access networkdevice 203, a possible case is that the first access network device 202has a relatively small coverage area. If the terminal device 201 ishanded over from a cell managed by the first access network device 202to a cell managed by the second access network device 203, there is aproblem: how to provide a solution of quick handover. The followingEmbodiment 3 and Embodiment 4 separately provide a solution to thisproblem. In the solution, the terminal device 201 not only establishesan air interface connection to the first access network device 202, butalso establishes an air interface connection to the second accessnetwork device 203. In this case, when the terminal device 201 movesfrom a coverage area of the cell managed by the first access networkdevice 202 to a coverage area of the cell managed by the second accessnetwork device 203, there is no need to establish an air interfaceconnection any further. This can implement a quick and seamlesshandover.

In Embodiment 1 and Embodiment 2, only an air interface between theterminal device 201 and the first access network device 202 isconfigured. In Embodiment 3 and Embodiment 4, not only a first airinterface between the terminal device 201 and the first access networkdevice 202 is configured, but also a second air interface between theterminal device 201 and the second access network device 203 isconfigured.

For ease of understanding, the following Table 1 lists main content ofembodiments of the present disclosure and related accompanying drawings.

TABLE 1 Embodi- Accompanying ment Main content drawing Embodi- Theterminal device 201 establishes an air FIG. 7 ment 1 interfaceconnection only to the first access network device 202, and the secondaccess network device 203 configures an air interface between the firstaccess network device 202 and the terminal device 201. Embodi- Theterminal device 201 establishes an air FIG. 8 ment 2 interfaceconnection only to the first access network device 202, and the firstaccess network device 202 configures an air interface between the firstaccess network device 202 and the terminal device 201. Embodi- Theterminal device 201 establishes an air FIG. 9 ment 3 interfaceconnection to both the first access network device 202 and the secondaccess network device 203, and the second access network device 203configures an air interface between the first access network device 202and the terminal device 201. Embodi- The terminal device 201 establishesan air FIG. 10 ment 4 interface connection to both the first accessnetwork device 202 and the second access network device 203, and thefirst access network device 202 configures an air interface between thefirst access network device 202 and the terminal device 201. Embodi-First type of second access network device FIG. 11 and ment 5 FIG. 12Embodi- First type of first access network device FIG. 13 and ment 6FIG. 14 Embodi- First type of terminal device FIG. 15 and ment 7 FIG. 16Embodi- Second type of second access network device FIG. 17 and ment 8FIG. 18 Embodi- Second type of first access network device FIG. 19 andment 9 FIG. 20 Embodi- Second type of terminal device FIG. 21 and ment10 FIG. 22

Embodiment 1

Embodiment 1 provides a solution for establishing an air interfaceconnection between a terminal device 201 and a first access networkdevice 202. The first access network device 202 cannot provide acomplete air interface protocol stack, and needs to provide a completeair interface protocol stack to the terminal device 201 together with asecond access network device 203.

Embodiment 1 may be applicable to protocol stack structures shown inFIG. 3A to FIG. 3D. Certainly, the protocol stack structures shown inFIG. 3A to FIG. 3D are only examples. Actually, Embodiment 1 isapplicable to any case in which two access network devices jointlyprovide a complete air interface protocol stack.

In Embodiment 1, a procedure in which the terminal device 201 interactswith the first access network device 202 and the second access networkdevice 203 is shown in FIG. 7. The procedure includes the followingsteps.

S701: The terminal device 201 sends an air interface establishmentrequest message to the second access network device 203 by using thefirst access network device 202, where the air interface establishmentrequest message is a message of an air interface protocol layer that isin a second air interface protocol layer between the terminal device 201and the second access network device 203 and that is used to configurean air interface; for example, if the second access network device 203is an LTE base station, the message may be the RRC connection requestmessage mentioned above.

After receiving the air interface establishment request message from theterminal device 201, the first access network device 202 forwards theair interface establishment request message to the second access networkdevice 203 over an interface, for example, an X5 interface, that hasbeen established between the first access network device 202 and thesecond access network device 203.

S702: After receiving the air interface establishment request messagefrom the terminal device 201, the second access network device 203 maysend a submessage 1 of a first air interface configuration message tothe first access network device 202, where the submessage 1 is sent tothe terminal device 201; after the terminal device 201 receives themessage, may configure a first air interface protocol layer between theterminal device 201 and the first access network device 202 and a secondair interface protocol layer between the terminal device 201 and thesecond access network device 203 according to configuration informationin the message.

In Embodiment 1 and Embodiment 2, an air interface configuration messagesent to the terminal device 201 by the second access network device 203by using the first access network device 202 is referred to as a “firstair interface configuration message”. A submessage 1 in the first airinterface configuration message and a submessage 2 in the first airinterface configuration message are used to jointly complete airinterface configuration for the terminal device 201. For example, thesubmessage 1 is used to configure the SRB 1 mentioned above, and thesubmessage 2 is used to configure the SRB 2 and the DRB that arementioned above.

In step S702, the second access network device 203 further sends asubmessage 1 of a second air interface configuration message to thefirst access network device 202, where the submessage 1 is sent to thefirst access network device 202; after receiving the submessage 1, thefirst access network device 202 may configure the first air interfaceprotocol layer between the first access network device 202 and theterminal device 201 according to configuration information in themessage.

In Embodiment 1 and Embodiment 2, an air interface configuration messagesent to the first access network device 202 by the second access networkdevice 203 is referred to as a “second air interface configurationmessage”. A submessage 1 and a submessage 2 that are in the second airinterface configuration message are used to jointly complete airinterface configuration performed by the first access network device202. The submessage 1 is used to configure a first air interfaceprotocol layer of the SRB 1 mentioned above, and the submessage 2 isused to configure a first air interface protocol layer of the SRB 2 andthe DRB that are mentioned above.

The submessage 1 of the first air interface configuration message andthe submessage 1 of the second air interface configuration message maybe sent to the first access network device 202 by using a same message,for example, sent by using a same X5 interface message, or separatelysent to the first access network device 202 and the terminal device 201by using independent messages.

The second access network device 203 may add, to a message of aninterface between the second access network device 203 and the firstaccess network device 202, the submessage 1 of the first air interfaceconfiguration message to be sent to the terminal device 201, and sendthe interface message to the first access network device 202. If thesecond access network device 203 is an LTE base station, the submessage1 may be an RRC connection setup message.

In step S702, if an air interface configuration manner in a current LTEsystem is used, the submessage 1 of the first air interfaceconfiguration message may include configuration information of an SRB 1,for example, the SRB ID, the RLC configuration information, and the LCHconfiguration information that are mentioned above, and configurationinformation of a MAC layer and a PHY layer.

According to regulations in the current 3^(rd) Generation PartnershipProject (3GPP) technical specification (TS) 36.331,RadioResourceConfigDedicated may include configuration information of aMAC layer and a PHY layer, and an SRB-ToAddModList, and anDRB-ToAddModList, There may be a plurality of SRBs.

Certainly, the RRC connection setup message is only an example. Thesubmessage 1 of the first air interface configuration message may alsobe sent by using another message format.

The submessage 1 of the second air interface configuration messagereceived by the first access network device 202 and the submessage 1 ofthe first air interface configuration message to be sent to the terminaldevice 201 by the second access network device 203 may have a sameformat. However, the first access network device 202 does not need toconfigure a complete air interface protocol stack. Therefore, the firstaccess network device 202 may extract, from the submessage 1 of thesecond air interface configuration message, configuration informationrelated to the first air interface protocol layer, and configure thefirst air interface protocol layer according to the extractedconfiguration information.

Alternatively, the second access network device 203 may add, to thesubmessage 1 of the second air interface configuration message, onlyconfiguration information related to the first air interface protocollayer, and send the submessage 1 to the first access network device 202.The first access network device 202 configures the first air interfaceprotocol layer according to the received configuration information.

S703: The first access network device 202 sends the submessage 1 of thefirst air interface configuration message to the terminal device 201,and after receiving the submessage 1 of the first air interfaceconfiguration message, the terminal device 201 may perform air interfaceconfiguration.

S704: After completing configuration according to the receivedsubmessage 1 of the first air interface configuration message, theterminal device 201 may send an air interface establishment responsemessage to the second access network device 203 by using the firstaccess network device 202, where if the second access network device 203is an LTE base station, the message may be the RRC connection setupcomplete message mentioned above.

Optionally, a processing manner in the current LTE system may be used,and the terminal device 201 adds an NAS message, for example, a servicerequest message, to the air interface establishment response message.

After receiving the air interface establishment response message fromthe terminal device 201, the second access network device 203 obtainsthe service request message from the air interface establishmentresponse message, and may add the obtained service request message to aninitial UE message that is to be sent to an MME. The MME sends aninitial context setup request message to the second access networkdevice 203. The initial context setup request message includes theaforementioned information required for configuring a DRB for theterminal device 201 by the second access network device 203, forexample, a UE AMBR or E-RAB QoS.

If the second access network device 203 is an LTE base station, for amanner of interacting between the LTE base station and the MME, refer toa manner in the current LTE system. The manner may includeauthentication, NAS security activation, location update, sessionestablishment, access stratum (AS) security activation, and the like.After security is activated, the second access network device 203 mayinitiate establishment of an SRB 2 link for subsequent transmission ofNAS signaling.

S705: The second access network device 203 sends a submessage 2 of thefirst air interface configuration message to the first access networkdevice 202, where the submessage 2 is sent to the terminal device 201;subsequently, in step S706, after the terminal device 201 receives themessage, may configure the first air interface protocol layer betweenthe terminal device 201 and the first access network device 202 and thesecond air interface protocol layer between the terminal device 201 andthe second access network device 203 according to configurationinformation in the message.

In step S705, the second access network device 203 may further send thesubmessage 2 of the second air interface configuration message to thefirst access network device 202, where the submessage 2 is sent to thefirst access network device 202; after receiving the submessage 2, thefirst access network device 202 may configure the first air interfaceprotocol layer between the first access network device 202 and theterminal device 201 according to configuration information in themessage.

The submessage 2 of the first air interface configuration message andthe submessage 2 of the second air interface configuration message maybe sent to the first access network device 202 by using a same message,for example, sent by using a same X5 interface message, or separatelysent to the first access network device 202 and the terminal device 201by using independent messages.

In step S705, if the air interface configuration manner in the currentLTE system is used, the submessage 2 of the first air interfaceconfiguration message may include configuration information of an SRB 2and a DRB.

For example, the DRB configuration information may include RLCconfiguration information, an LCH ID, LCH configuration information,configuration information of a. MAC layer and a PITY layer, and thelike. DRB configuration information of the second air interface protocollayer between the terminal device 201 and the second access networkdevice 203 may include an EPS bearer ID, a DRB ID, PDCP configurationinformation, and the like.

For example, the SRB 2 configuration information may include SRB ID, RLCconfiguration information, LCH configuration information, andconfiguration information of a MAC layer and a PHY layer.

The configuration information of a MAC layer and a PHY layer of the DRBis the same as or different from that of the SRB 2.

Certainly, an RRC connection reconfiguration message is only an example.The submessage 2 of the first air interface configuration message mayalso be sent by using another message format.

The submessage 2 of the second air interface configuration messagereceived by the first access network device 202 and the submessage 2 ofthe first air interface configuration message to be sent to the terminaldevice 201 by the second access network device 203 may have a sameformat. However, the first access network device 202 does not need toconfigure a complete air interface protocol stack. Therefore, the firstaccess network device 202 may extract, from the submessage 2 of thesecond air interface configuration message, configuration informationrelated to the first air interface protocol layer, and configure thefirst air interface protocol layer according to the extractedconfiguration information.

Alternatively, the second access network device 203 may add, to thesubmessage 2 of the second air interface configuration message, onlyconfiguration information related to the first air interface protocollayer, and send the submessage 2 to the first access network device 202.The first access network device 202 configures the first air interfaceprotocol layer according to the received configuration information.

Embodiment 1 is described above, in Embodiment 1, the first accessnetwork device 202 configures an air interface between the first accessnetwork device 202 and the terminal device 201 according to the secondair interface configuration message received from the second accessnetwork device 203. Different from that in Embodiment 1, in Embodiment2, the first access network device 202 determines configurationinformation of a first air interface protocol layer between the firstaccess network device 202 and the terminal device 201, and sends thedetermined configuration information of the first air interface protocollayer to the second access network device 203 by using a third airinterface configuration message; in a first air interface configurationmessage sent to the terminal device 201 by the second access networkdevice 203, the configuration information of the first air interfaceprotocol layer is sent to the terminal device 201 by the second accessnetwork device 203 after being obtained from the third air interfaceconfiguration message sent by the first access network device 202.

Embodiment 2

Embodiment 2 provides a solution for establishing an air interfaceconnection between a terminal device 201 and a first access networkdevice 202. The first access network device 202 cannot provide acomplete air interface protocol stack, and needs to provide a completeair interface protocol stack to the terminal device 201 together with asecond access network device 203.

Embodiment 2 may be applicable to protocol stack structures shown inFIG. 3A to FIG. 3D. Certainly, the protocol stack structures shown inFIG. 3A to FIG. 3D are only examples. Actually, Embodiment 2 isapplicable to any case in which two access network devices jointlyprovide a complete air interface protocol stack.

In Embodiment 2, a procedure in which the terminal device 201 interactswith the first access network device 202 and the second access networkdevice 203 is shown in FIG. 8. The procedure includes the followingsteps.

S801: The terminal device 201 sends an air interface establishmentrequest message to the second access network device 203 by using thefirst access network device 202, where for specific implementation ofthe air interface establishment request message, refer to step S701.

After receiving the air interface establishment request message from theterminal device 201, the first access network device 202 forwards theair interface establishment request message to the second access networkdevice 203 over an interface, for example, an X5 interface, that hasbeen established between the first access network device 202 and thesecond access network device 203.

S802: The first access network device 202 determines configurationinformation of a first air interface protocol layer between the firstaccess network device 202 and the terminal device 201, and sends asubmessage 1 of a third air interface configuration message to thesecond access network device 203, where the submessage 1 carries thedetermined configuration information of the first air interface protocollayer.

In Embodiment 2, an air interface configuration message sent to thesecond access network device 203 by the first access network device 202is referred to as a “third air interface configuration message”. Asubmessage 1 and a submessage 2 that are in the third air interfaceconfiguration message together include complete air interfaceconfiguration information from the first access network device 202. Forexample, the submessage 1 includes configuration information of a firstair interface protocol layer of an SRB 1, and the submessage 2 includesconfiguration information of a first air interface protocol layer of anSRB 2 and a DRB.

The submessage 1 of the third air interface configuration message andthe air interface establishment request in step S801 may be sent to thesecond access network device 203 together, for example, sent by using asame X5 interface message, or separately sent to the second accessnetwork device 203 by using independent messages.

In step S802, if an air interface configuration manner in a current LTEsystem is used, the submessage 1 of the third air interfaceconfiguration message may include configuration information of a firstair interface protocol layer of an SRB 1. The message may be sent to thesecond access network device 203 by using a container form, and thesecond access network device 203 cannot read the message, and directlycopies the message into a submessage 1 of a first air interfaceconfiguration message that is to be sent to the terminal device 201subsequently. Alternatively, the message may be sent by using anon-container form, and the second access network device 203 can readcontent in the message.

Optionally, the first access network device 202 may configure the firstair interface protocol layer after determining the configurationinformation of the first air interface protocol layer between the firstaccess network device 202 and the terminal device 201, or may configurethe first air interface protocol layer after receiving a first airinterface configuration message from the second access network device203 in step S803.

S803: The second access network device 203 sends a submessage 1 of afirst air interface configuration message to the first access networkdevice 202 over an interface between the second access network device203 and the first access network device 202, and after receiving thesubmessage 1, the first access network device 202 forwards thesubmessage 1 to the terminal device 201.

For a sending manner and message content that are of the submessage 1 ofthe first air interface configuration message, refer to the descriptionof Embodiment 1. Details are not repeated herein any further.

After receiving the submessage 1 of the first air interfaceconfiguration message, the terminal device 201 may perform air interfaceconfiguration.

S804: After completing configuration according to the receivedsubmessage 1 of the first air interface configuration message, theterminal device 201 may send an air interface establishment responsemessage to the second access network device 203 by using the firstaccess network device 202.

For specific implementation of the air interface establishment responsemessage and content included in the message, refer to the description ofstep S704.

If the air interface establishment response message includes a servicerequest message, after receiving the air interface establishmentresponse message from the terminal device 201, the second access networkdevice 203 obtains the service request message from the air interfaceestablishment response message, and may add the obtained service requestmessage to an initial UE message that is to be sent to an MME. The MMEsends an initial context setup request message to the second accessnetwork device 203. The initial context setup request message includesthe aforementioned information required for configuring a DRB for theterminal device 201 by the second access network device 203, forexample, a UE AMBR or E-RAB QoS.

For a manner of interacting between the second access network device 203and the MME, refer to the description of step S704.

S805: The second access network device 203 sends an air interfaceconfiguration request message to the first access network device 202.

The second access network device 203 may add information to the message.A manner of adding the information includes but is not limited to thefollowing two manners:

Manner 1:

The air interface configuration request message carries contextinformation of the terminal device 201. For example, if a manner usedwhen an LTE base station in an UT system sets an RRC reconfigurationmessage is used, the second access network device 203 may send thefollowing information to the first access network device 202: an AMBR,E-RAB QoS, and the like of the terminal device 201. After receiving theinformation, the first access network device 202 determines, accordingto the message, configuration information of a first air interfaceprotocol layer of a user plane between the first access network device202 and the terminal device 201, that is, determines configurationinformation of a first air interface protocol layer of a DRB.

Manner 2:

The air interface configuration message carries configurationinformation of a second air interface protocol layer between the secondaccess network device 203 and the terminal device 201, for example,configuration information of a second air interface protocol layer of aDRB, for example, an EPS bearer ID, a DRB ID, or PDCP configurationinformation. After receiving the information, the first access networkdevice 202 determines configuration information of a first air interfaceprotocol layer of a DRB between the first access network device 202 andthe terminal device 201, for example, make an LCH ID correspond to theDRB ID.

In addition, the first access network device 202 may further determine aconfiguration parameter of a first air interface protocol layer of anSRB 2 between the first access network device 202 and the terminaldevice 201.

S806: The first access network device 202 sends a submessage 2 of thethird air interface configuration message to the second access networkdevice 203, where the submessage 2 includes configuration informationthat is of a first air interface protocol layer and that is determinedin step S805, for example, a configuration parameter of a first airinterface protocol layer of an SRB 2 and a DRB.

S807: The second access network device 203 sends a submessage 2 of thefirst air interface configuration message to the terminal device 201 byusing the first access network device 202, where the submessage is sentto the terminal device 201, and after receiving the submessage 2, theterminal device 201 configures an air interface according toconfiguration information in the message.

For a sending manner and message content that are of the submessage 2 ofthe first air interface configuration message, refer to the descriptionof Embodiment 1. Details are not repeated herein any further.

Optionally, the first access network device 202 may configure the firstair interface protocol layer after determining, in step S806, theconfiguration information of the first air interface protocol layerbetween the first access network device 202 and the terminal device 201,or may configure the first air interface protocol layer after receivingthe first air interface configuration message from the second accessnetwork device 203 in step S807.

Embodiment 1 and Embodiment 2 are described above. The two embodimentsare applicable to a case shown in FIG. 2A, that is, the terminal device201 establishes an air interface connection only to the first accessnetwork device 202, and the terminal device 201 may be connected to acore network by using the first access network device 202 and the secondaccess network device 203. Therefore, in Embodiment 1 and Embodiment 2,during air interface configuration, only the first air interfaceprotocol layer between the terminal device 201 and the first accessnetwork device 202 and the second air interface protocol layer betweenthe terminal device 201 and the second access network device 203 need tobe configured.

Embodiment 3 and Embodiment 4 are described in the following. Embodiment3 and Embodiment 4 are different from the foregoing two embodiments inthe following: Embodiment 3 and Embodiment 4 are applicable to a caseshown in FIG. 2B, that is, the terminal device 201 not only establishesan air interface connection of a first air interface to the first accessnetwork device 202, but also establishes an air interface connection ofa second air interface to the second access network device 203. InEmbodiment 3 and Embodiment 4, during air interface configuration, notonly each air interface protocol layer of the first air interfacebetween the terminal device 201 and the first access network device 202needs to be configured, but also an air interface protocol layer of thesecond air interface between the terminal device 201 and the secondaccess network device 203 needs to be configured.

Embodiment 3

Embodiment 3 provides a solution for establishing an air interfaceconnection between a terminal device 201 and a first access networkdevice 202 and between the terminal device 201 and a second accessnetwork device 203. On a first air interface between the terminal device201 and the first access network device 202, the first access networkdevice 202 cannot provide a complete air interface protocol stack, andneeds to provide a complete air interface protocol stack to the terminaldevice 201 together with the second access network device 203.

Embodiment 3 may be applicable to protocol stack structures shown inFIG. 4A to FIG. 4D. Certainly, the protocol stack structures shown inFIG. 4A to FIG. 4D are only examples. Actually, Embodiment 3 isapplicable to any case in which two access network devices jointlyprovide a complete air interface protocol stack of an air interface, andanother access network device provides a complete air interface protocolstack.

In Embodiment 3, a procedure in which the terminal device 201 interactswith the first access network device 202 and the second access networkdevice 203 is shown in FIG. 9. The procedure includes the followingsteps.

S901: The terminal device 201 sends an air interface establishmentrequest message to the second access network device 203 by using thefirst access network device 202, where for an optional implementation ofthe air interface establishment request message, refer to thedescription of step S701.

After receiving the air interface establishment request message from theterminal device 201, the first access network device 202 forwards theair interface establishment request message to the second access networkdevice 203 over an interface, for example, an X5 interface, that hasbeen established between the first access network device 202 and thesecond access network device 203.

S902: After receiving the air interface establishment request messagefrom the terminal device 201, the second access network device 203 maysend a submessage 3 of a first air interface configuration message tothe first access network device 202, where the submessage 3 is sent tothe terminal device 201 and includes configuration information of afirst air interface and a second air interface, after receiving themessage, the terminal device 201 may configure the first air interfacebetween the terminal device 201 and the first access network device 202and the second air interface between the terminal device 201 and thesecond access network device 203 according to the configurationinformation in the message.

In Embodiment 3 and Embodiment 4, an air interface configuration messagesent to the terminal device 201 by the second access network device 203by using the first access network device 202 is referred to as a “firstair interface configuration message”. A submessage 3 in the first airinterface configuration message and a submessage 4 in the first airinterface configuration message are used to jointly complete airinterface configuration for the terminal device 201. For example, thesubmessage 3 is used to configure an SRB 1 of the first air interfaceand an SRB 1 of the second air interface, and the submessage 4 is usedto configure an SRB 2 and a DRB that are of the first air interface andthe second air interface.

In step S902, the second access network device 203 further sends asubmessage 3 of a second air interface configuration message to thefirst access network device 202, where the submessage 3 is sent to thefirst access network device 202. After receiving the submessage 3, thefirst access network device 202 may configure a first air interfaceprotocol layer between the first access network device 202 and theterminal device 201 according to configuration information in themessage.

In Embodiment 3 and Embodiment 4, an air interface configuration messagesent to the first access network device 202 by the second access networkdevice 203 is referred to as a “second air interface configurationmessage”. A submessage 3 and a submessage 4 that are in the second airinterface configuration message are used to jointly complete airinterface configuration performed by the first access network device202. The submessage 3 is used to configure a first air interfaceprotocol layer of the SRB 1 mentioned above, and the submessage 4 isused to configure a first air interface protocol layer of the SRB 2, andthe DRB that are mentioned above.

The submessage 3 of the first air interface configuration message andthe submessage 3 of the second air interface configuration message maybe sent to the first access network device 202 by using a same message,for example, sent by using a same X5 interface message, or separatelysent to the first access network device 202 and the terminal device 201by using independent messages.

The second access network device 203 may add, to a message of aninterface between the second access network device 203 and the firstaccess network device 202, the submessage 3 of the first air interfaceconfiguration message to be sent to the terminal device 201, and sendthe interface message to the first access network device 202. If thesecond access network device 203 is an LTE base station, the submessage3 may be an RRC connection setup message.

For the configuration information of the first air interface in thesubmessage 3 of the first air interface configuration message, refer tothe aforementioned submessage 1 in the first air interface configurationmessage in Embodiment 1.

In step S902, if an air interface configuration manner in a current LTEsystem is used, the submessage 3 of the first air interfaceconfiguration message may include configuration information of an SRB 1,for example, the SRB ID, the RLC configuration information, and the LCHconfiguration information that are mentioned above, and configurationinformation of a MAC layer and a PHY layer.

Certainly, the RRC connection setup message is only an example. Thesubmessage 3 of the first air interface configuration message may alsobe sent by using another message format.

S903: The first access network device 202 sends the submessage 3 of thefirst air interface configuration message to the terminal device 201,and after receiving the submessage 3 of the first air interfaceconfiguration message, the terminal device 201 may perform air interfaceconfiguration, that is, configure the first air interface and the secondair interface.

S904: After completing configuration according to the receivedsubmessage 3 of the first air interface configuration message, theterminal device 201 may send an air interface establishment responsemessage to the second access network device 203 by using the firstaccess network device 202, where if the second access network device 203is an LTE base station, the message may be the RRC connection setupcomplete message mentioned above.

Alternatively, because the SRB 1 of the second air interface between theterminal device 201 and the second access network device 203 is alsoestablished, the terminal device 201 may send an air interfaceestablishment response to the second access network device 203 directlyover the second air interface.

Optionally, a processing manner in the current LTE system may be used,and the terminal device 201 adds an NAS message, for example, a servicerequest message, to the air interface establishment response message.

After receiving the air interface establishment response message fromthe terminal device 201, the second access network device 203 obtainsthe service request message from the air interface establishmentresponse message, and may add the obtained service request message to aninitial UE message that is to be sent to an MME. The MME sends aninitial context setup request message to the second access networkdevice 203. The initial context setup request message includes theaforementioned information required for configuring a DRB for theterminal device 201 by the second access network device 203, forexample, a UE AMBR or E-RAB QoS.

In addition, the initial context setup request message may furtherinclude capability information of the terminal device 201. As mentionedabove, the terminal device 201 may communicate with the first accessnetwork device 202 and the second access network device 203 in a DCmanner or a CA manner. Herein, the capability information of theterminal device 201 may be used to indicate whether the terminal device201 supports both the DC manner and the CA manner.

If the second access network device 203 is an LTE base station, for amanner of interacting between the LTE base station and the MME, refer toa manner in the current LTE system. The manner may includeauthentication, NAS security activation, location update, sessionestablishment, AS security activation, and the like. After security isactivated, the second access network device 203 may initiateestablishment of an SRB 2 link for subsequent transmission of NASsignaling.

Optionally, if the terminal device 201 supports both the DC manner andthe CA manner, the second access network device 203 may send ameasurement configuration to the terminal device 201 by using the firstaccess network device 202, and then, the terminal device 201 may send ameasurement result to the second access network device 203 by using thefirst access network device 202. The second access network device 203may select, for the terminal device 201 according to the receivedmeasurement result and a known status of a cell managed by the secondaccess network device 203, a proper cell for access.

S905: The second access network device 203 sends a submessage 4 of thefirst air interface configuration message to the first access networkdevice 202, where the submessage 4 is sent to the terminal device 201and includes the configuration information of the first air interfaceand the second air interface; after receiving the message, the terminaldevice 201 may configure the first air interface between the terminaldevice 201 and the first access network device 202 and the second airinterface between the terminal device 201 and the second access networkdevice 203 according to the configuration information in the message.

In step S905, the second access network device 203 may further send thesubmessage 4 of the second air interface configuration message to thefirst access network device 202, where the submessage 4 is sent to thefirst access network device 202, and includes configuration informationof the first air interface protocol layer of the first air interfacebetween the first access network device 202 and the terminal device 201;after receiving the submessage 4, the first access network device 202may configure the first air interface protocol layer of the first airinterface according to the configuration information in the message.

The submessage 4 of the first air interface configuration message andthe submessage 4 of the second air interface configuration message maybe sent to the first access network device 202 by using a same message,for example, sent by using a same X5 interface message, or separatelysent to the first access network device 202 and the terminal device 201by using independent messages.

In step S905, if the air interface configuration manner in the currentLTE system is used, the submessage 4 of the first air interfaceconfiguration message may include configuration information of an SRB 2and a DRB.

For example, the DRB configuration information may include RLCconfiguration information, an LCH ID, LCH configuration information,configuration information of a MAC layer and a PRY layer, and the like.DRB configuration information of a second air interface protocol layeror a fourth air interface protocol layer between the terminal device 201and the second access network device 203 may include an EPS bearer ID, aDRB ID, PDCP configuration information, and the like.

For example, the SRB 2 configuration information may include an SRB ID,RLC configuration information, LCH configuration information, andconfiguration information of a MAC layer and a PHY layer.

The configuration information of a MAC layer and a PHY layer of the DRBis the same as or different from that of the SRB 2.

Certainly, an RRC connection reconfiguration message is only an example.The submessage 4 of the first air interface configuration message mayalso be sent by using another message format.

If the first access network device 202 and the second access networkdevice 203 are co-located with same coverage, after configuring thesecond air interface, the terminal device 201 may transmit data and anNAS message directly over the second air interface.

If the first access network device 202 and the second access networkdevice 203 do not have same coverage, an optional implementation is thatthe terminal device 201 can transmit data and an NAS message over thesecond air interface only after performing random access over the secondair interface. Therefore, in this case, in addition to the foregoinginformation, the submessage 4 of the first air interface configurationmessage may include access information, and the terminal device 201 mayaccess, according to the access information, a cell managed by thesecond access network device 203. In addition, the message may includecell information of the cell that is managed by the second accessnetwork device 203 and that the terminal device 201 can access.Certainly, the access information and the cell information mayalternatively be carried in a subsequent air interface configurationmessage, for example, an RRC message.

Embodiment 3 is described above. In Embodiment 3, the first accessnetwork device 202 configures the first air interface between the firstaccess network device 202 and the terminal device 201 according to thesecond air interface configuration message received from the secondaccess network device 203. Different from that in Embodiment 3, inEmbodiment 4, the first access network device 202 determinesconfiguration information of a first air interface protocol layer of afirst air interface between the first access network device 202 and theterminal device 201, and sends the determined configuration informationof the first air interface protocol layer of the first air interface tothe second access network device 203 by using a third air interfaceconfiguration message in a first air interface configuration messagesent to the terminal device 201 by the second access network device 203,the configuration information of the first air interface protocol layerof the first air interface is sent to the terminal device 201 afterbeing obtained by the second access network device 203 from the thirdair interface configuration message sent by the first access networkdevice 202.

Embodiment 4

Embodiment 4 provides a solution for establishing an air interfaceconnection between a terminal device 201 and a first access networkdevice 202 and between the terminal device 201 and a second accessnetwork device 203. On a first air interface between the terminal device201 and the first access network device 202, the first access networkdevice 202 cannot provide a complete air interface protocol stack, andneeds to provide a complete air interface protocol stack to the terminaldevice 201 together with the second access network device 203.

Embodiment 4 may be applicable to protocol stack structures shown inFIG. 4A to FIG. 4D. Certainly, the protocol stack structures shown inFIG. 4A to FIG. 4D are only examples. Actually, Embodiment 4 isapplicable to any case in which two access network devices jointlyprovide a complete air interface protocol stack of an air interface, andanother access network device provides a complete air interface protocolstack.

In Embodiment 4, a procedure in which the terminal device 201 interactswith the first access network device 202 and the second access networkdevice 203 is shown in FIG. 10. The procedure includes the followingsteps.

S1001: The terminal device 201 sends an air interface establishmentrequest message to the second access network device 203 by using thefirst access network device 202, where for an optional implementation ofthe air interface establishment request message, refer to thedescription of step S701.

After receiving the air interface establishment request message from theterminal device 201, the first access network device 202 forwards theair interface establishment request message to the second access networkdevice 203 over an interface, for example, an X5 interface, that hasbeen established between the first access network device 202 and thesecond access network device 203.

S1002: The first access network device 202 determines configurationinformation of a first air interface protocol layer of a first airinterface between the first access network device 202 and the terminaldevice 201, and sends a submessage 3 of a third air interfaceconfiguration message to the second access network device 203, where thesubmessage 3 carries the determined configuration information of thefirst air interface protocol layer of the first air interface.

In Embodiment 4, an air interface configuration message sent to thesecond access network device 203 by the first access network device 202is referred to as a “third air interface configuration message”. Asubmessage 3 and a submessage 4 that are in the third air interfaceconfiguration message together include complete air interfaceconfiguration information from the first access network device 202. Forexample, the submessage 3 includes configuration information of a firstair interface protocol layer of an SRB 1, where the SRB 1 is of thefirst air interface, and the submessage 4 includes configurationinformation of a first air interface protocol layer of an SRB 2 and aDRB, where the SRB 2 and the DRB are of the first air interface.

The submessage 3 of the third air interface configuration message andthe air interface establishment request in step S1001 may be sent to thesecond access network device 203 together, for example, sent by using asame X5 interface message, or separately sent to the second accessnetwork device 203 by using independent messages.

In step S1002, if an air interface configuration manner in a current LTEsystem is used the submessage 3 of the third air interface configurationmessage may include configuration information of a first air interfaceprotocol layer of an SRB 1, where the SRB 1 is of the first airinterface. The message may be sent to the second access network device203 by using a container form, and the second access network device 203cannot read the message, and directly copies the message into asubmessage 3 of a first air interface configuration message that is tobe sent to the terminal device 201 subsequently. Alternatively, themessage may be sent by using a non-container form, and the second accessnetwork device 203 can read content in the message.

Optionally, the first access network device 202 may configure the firstair interface protocol layer after determining the configurationinformation of the first air interface protocol layer of the first airinterface between the first access network device 202 and the terminaldevice 201, or may configure the first air interface protocol layerafter receiving a first air interface configuration message from thesecond access network device 203 in step S1003.

S1003: The second access network device 203 sends a submessage 3 of afirst air interface configuration message to the first access networkdevice 202 over an interface between the second access network device203 and the first access network device 202, and after receiving thesubmessage 3, the first access network device 202 forwards thesubmessage 3 to the terminal device 201.

For a sending manner and message content that are of the submessage 3 ofthe first air interface configuration message, refer to the descriptionof Embodiment 3. Details are not repeated herein any further.

After receiving the submessage 3 of the first air interfaceconfiguration message, the terminal device 201 may configure the firstair interface and a second air interface.

S1004: After completing configuration according to the receivedsubmessage 3 of the first air interface configuration message, theterminal device 201 may send an air interface establishment responsemessage to the second access network device 203 by using the firstaccess network device 202, where for an optional implementation of theair interface establishment response message, refer to step S904.

Alternatively, because an SRB 1 of the second air interface between theterminal device 201 and the second access network device 203 is alsoestablished, the terminal device 201 may send an air interfaceestablishment response to the second access network device 203 directlyover the second air interface.

Optionally, a processing manner in the current LTE system may be used,and the terminal device 201 adds an NAS message, for example, a servicerequest message, to the air interface establishment response message.

After receiving the air interface establishment response message fromthe terminal device 201, the second access network device 203 obtainsthe service request message from the air interface establishmentresponse message, and may add the obtained service request message to aninitial UE message that is to be sent to an MME. The MME sends aninitial context setup request message to the second access networkdevice 203. The initial context setup request message includes theaforementioned information required for configuring a DRB for theterminal device 201 by the second access network device 203, forexample, a UE AMBR or E-RAB QoS.

In addition, the initial context setup request message may furtherinclude capability information of the terminal device 201. As mentionedabove, the terminal device 201 may communicate with the first accessnetwork device 202 and the second access network device 203 in a DCmanner or a CA manner. Herein, the capability information of theterminal device 201 may be used to indicate whether the terminal device201 supports both the DC manner and the CA manner.

If the second access network device 203 is an LTE base station, for amanner of interacting between the LTE base station and the MME, refer toa manner in the current LTE system. The manner may includeauthentication, NAS security activation, location update, sessionestablishment, AS security activation, and the like. After security isactivated, the second access network device 203 may initiateestablishment of an SRB 2 link for subsequent transmission of NASsignaling.

Optionally, if the terminal device 201 supports both the DC manner andthe CA manner, the second access network device 203 may send ameasurement configuration to the terminal device 201 by using the firstaccess network device 202, and then, the terminal device 201 may send ameasurement result to the second access network device 203 by using thefirst access network device 202. The second access network device 203may select, for the terminal device 201 according to the receivedmeasurement result and a known status of a cell managed by the secondaccess network device 203, a proper cell for access.

S1005: The second access network device 203 sends an air interfaceconfiguration request message to the first access network device 202.

For a manner of carrying information by the air interface configurationrequest message, refer to step S805.

In addition, the first access network device 202 may further determine aconfiguration parameter of a first air interface protocol layer of anSRB 2 between the first access network device 202 and the terminaldevice 201.

S1006: The first access network device 202 sends a submessage 4 of thethird air interface configuration message to the second access networkdevice 203, where the submessage 4 includes the configurationinformation that is of the first air interface protocol layer of thefirst air interface and that is determined in step S1002, for example, aconfiguration parameter of a first air interface protocol layer of anSRB 2 and a DRB, where the SRB 2 and the DRB are of the first airinterface.

S1007: The second access network device 203 sends a submessage 4 of thefirst air interface configuration message to the first access networkdevice 202, where the submessage 4 is sent to the terminal device 201and includes configuration information of the first air interface and asecond air interface; after receiving the message, the terminal device201 may configure the first air interface between the terminal device201 and the first access network device 202 and the second air interfacebetween the terminal device 201 and the second access network device 203according to the configuration information the message.

For content and a sending manner that are of the submessage 4, refer tothe related description of step S905.

Embodiment 5

FIG. 11 is a schematic structural diagram of a second access networkdevice according to Embodiment 5. As shown in FIG. 11, the second accessnetwork device includes:

a processing module 1101, configured to determine air interfaceconfiguration information of an air interface between a terminal deviceand a radio access network; and

a sending module 1102, configured to send a first air interfaceconfiguration message including the air interface configurationinformation to a first access network device in the radio accessnetwork, where the first access network device and the second accessnetwork device use different wireless communications standards;

the air interface between the terminal device and the radio accessnetwork includes a first air interface protocol layer and a second airinterface protocol layer; the first air interface protocol layer isbetween the terminal device and the first access network device, thesecond air interface protocol layer is between the terminal device andthe second access network device, and the second air interface protocollayer is above the first air interface protocol layer; and the first airinterface configuration message is a message of an air interfaceprotocol layer that is in the second air interface protocol layer andthat is used to configure an air interface.

The second access network device may further include a receiving module,configured to receive a message and/or data that are/is sent by thefirst access network device.

For another optional implementation of the second access network device,refer to implementation of the second access network device 203 inEmbodiment 1 or Embodiment 2. The processing module 1101 may beconfigured to perform processing and control operations of the secondaccess network device 203. The sending module 1102 may be configured toperform an operation of sending information to the first access networkdevice 202 by the second access network device 203. The receiving modulemay be configured to perform an operation of receiving information fromthe first access network device 202 by the second access network device203.

For a procedure in which the second access network device interacts withthe first access network device, refer to the procedure in which thesecond access network device 203 interacts with the first access networkdevice 202 in the procedure shown in FIG. 7 or FIG. 8. For content and astructure of a message sent or received by the second access networkdevice, also refer to the description of the procedure.

An optional implementation of the second access network device may beshown in FIG. 12. A processor 1201 may be configured to implement afunction of the processing module 1101. A transmitter 1202 may beconfigured to implement a function of the sending module 1102.Optionally, a receiver may further be included, and may be configured toimplement a function of the receiving module. In addition, the secondaccess network device may further include a memory, configured to storea program and data. The processor 1201 may perform processing andcontrol by invoking the program stored in the memory.

If the second access network device and the first access network devicecommunicate with each other by means of optical fiber transmission, thetransmitter 1202 may be an optical transmitter, and the receiver may bean optical receiver. If the second access network device and the firstaccess network device communicate with each other by means of microwavetransmission, the transmitter 1202 may be a microwave transmitter, andthe receiver may be a microwave receiver.

In addition, the second access network device may further include aradio frequency transceiver that communicates with the terminal device.

The transmitter 1202, the memory, and the receiver each may be directlyconnected to the processor 1201. Alternatively, the transmitter 1202,the memory, the receiver, and the processor 1201 each are connected to abus, and the components communicate with each other by using the bus.

Embodiment 6

FIG. 13 is a schematic structural diagram of a first access networkdevice according to Embodiment 6. As shown in FIG. 13, the first accessnetwork device includes:

a receiving module 1301, configured to receive a first air interfaceconfiguration message from a second access network device in a radioaccess network, where the first access network device and the secondaccess network device use different wireless communications standards,and the first air interface configuration message includes air interfaceconfiguration information of an air interface between a terminal deviceand the radio access network; and

a first sending module 1302, configured to send the first air interfaceconfiguration message to the terminal device, where

the air interface between the terminal device and the radio accessnetwork includes a first air interface protocol layer and a second airinterface protocol layer; the first air interface protocol layer isbetween the terminal device and the first access network device, thesecond air interface protocol layer is between the terminal device andthe second access network device, and the second air interface protocollayer is above the first air interface protocol layer; and the first airinterface configuration message is a message of an air interfaceprotocol layer that is in the second air interface protocol layer andthat is used to configure an air interface.

The first access network device may further include a processing module,configured to perform processing and control operations of the firstaccess network device.

For another optional implementation of the first access network device,refer to implementation of the first access network device 202 inEmbodiment 1 or Embodiment 2. The processing module may be configured toperform processing and control operations of the first access networkdevice 202. The first sending module 1302 may be configured to performan operation of sending information to the terminal device 201 by thefirst access network device 202. The receiving module 1301 may beconfigured to perform an operation of receiving information from thesecond access network device 203 by the first access network device 202.

For a procedure in which the first access network device interacts withthe second access network device and the terminal device, refer to theprocedure in which the first access network device 202 interacts withthe second access network device 203 and the terminal device 201 in theprocedure shown in FIG. 7 or FIG. 8. For content and a structure of amessage sent or received by the first access network device, also referto the description of the procedure.

An optional implementation of the first access network device may beshown in FIG. 14. A first transmitter 1402 may be configured toimplement a function of the first sending module 1302. A receiver 1401may be configured to implement a function of the receiving module 1301.A processor may further be included, and may be configured to implementa function of the processing module. In addition, the first accessnetwork device may further include a memory, configured to store aprogram and data. The processor may perform processing and control byinvoking the program stored in the memory.

The first transmitter 1402 may be a radio frequency transmitter. If thefirst access network device and the second access network devicecommunicate with each other by means of optical fiber transmission, thereceiver 1401 may be an optical receiver. If the first access networkdevice and the second access network device communicate with each otherby means of microwave transmission, the receiver 1401 may be a microwavereceiver.

In addition, the first access network device may further include a radiofrequency receiver receiving a message and/or data that are/is sent bythe terminal device, and a second transmitter sending a message and/ordata to the second access network device. The second transmitter may bean optical transmitter, a microwave transmitter, or the like.

The first transmitter 1402, the memory, and the receiver 1401 each maybe directly connected to the processor. Alternatively, the firsttransmitter 1402, the memory, the receiver 1401, and the processor eachare connected to a bus, and the components communicate with each otherby using the bus.

Embodiment 7

FIG. 15 is a schematic structural diagram of a terminal device accordingto Embodiment 7. As shown in FIG. 15, the terminal device includes:

a receiving module 1501, configured to receive a first air interfaceconfiguration message from a first access network device, where thefirst air interface configuration message is from a second accessnetwork device, and is forwarded by the first access network device; thefirst access network device and the second access network device arelocated in a same radio access network, the first access network deviceand the second access network device use different wirelesscommunications standards; and the first air interface configurationmessage includes air interface configuration information of an airinterface between the terminal device and the radio access network; and

a processing module 1502, configured to obtain the air interfaceconfiguration information from the first air interface configurationmessage, and configure the air interface between the terminal device andthe radio access network according to the air interface configurationinformation, where

the air interface between the terminal device and the radio accessnetwork includes a first air interface protocol layer and a second airinterface protocol layer; the first air interface protocol layer isbetween the terminal device and the first access network device, thesecond air interface protocol layer is between the terminal device andthe second access network device, and the second air interface protocollayer is above the first air interface protocol layer; and the first airinterface configuration message is a message of an air interfaceprotocol layer that is in the second air interface protocol layer andthat is used to configure an air interface.

The terminal device may further include a sending module, configured tosend a message and/or data to the first access network device and/or thesecond access network device.

For another optional implementation of the terminal device, refer toimplementation of the terminal device 201 in Embodiment 1 or Embodiment2. The processing module 1502 may be configured to perform processingand control operations of the terminal device 201. The sending modulemay be configured to perform an operation of sending information to thefirst access network device 202 or the second access network device 203by the terminal device 201. The receiving module 1501 may be configuredto perform an operation of receiving information from the second accessnetwork device 203 or the first access network device 202 by theterminal device 201.

For a procedure in which the terminal device interacts with the secondaccess network device and the first access network device, refer to theprocedure in which the terminal device 201 interacts with the secondaccess network device 203 and the first access network device 202 in theprocedure shown in FIG. 7 or FIG. 8. For content and a structure of amessage sent or received by the terminal device, also refer to thedescription of the procedure.

An optional implementation of the terminal device may be shown in FIG.16. A processor 1602 may be configured to implement a function of theprocessing module 1502. A receiver 1601 may be configured to implement afunction of the receiving module 1501. Optionally, a transmitter mayfurther be included, and may be configured to implement a function ofthe sending module. In addition, the terminal device may further includea memory, configured to store a program and data. The processor 1602 mayperform processing and control by invoking the program stored in thememory.

The transmitter may be a radio frequency transmitter. The receiver 1601may be a radio frequency receiver.

The transmitter, the memory, and the receiver 1601 each may be directlyconnected to the processor 1602. Alternatively, the transmitter, thememory, the receiver 1601, and the processor 1602 each are connected toa bus, and the components communicate with each other by using the bus.

Embodiment 8

FIG. 17 is a schematic structural diagram of a second access networkdevice according to Embodiment 8. As shown in FIG. 17, the second accessnetwork device includes:

a processing module 1701, configured to determine air interfaceconfiguration information of an air interface between a terminal deviceand a radio access network; and

a sending module 1702, configured to send a first air interfaceconfiguration message including the air interface configurationinformation to a first access network device in the radio accessnetwork, where

the first access network device and the second access network device usedifferent wireless communications standards; the air interface betweenthe terminal device and the radio access network includes a first airinterface and a second air interface; the first air interface includes afirst air interface protocol layer and a second air interface protocollayer, the first air interface protocol layer is between the terminaldevice and the first access network device, the second air interfaceprotocol layer is between the terminal device and the second accessnetwork device, and the second air interface protocol layer is above thefirst air interface protocol layer; the second air interface is an airinterface between the terminal device and the second access networkdevice; and the first air interface configuration message is a messageof an air interface protocol layer that is included in the second airinterface and that is used to configure an air interface.

The second access network device may further include a receiving module,configured to receive a message and/or data that are/is sent by thefirst access network device.

For another optional implementation of the second access network device,refer to implementation of the second access network device 203 inEmbodiment 3 or Embodiment 4. The processing module 1701 may beconfigured to perform processing and control operations of the secondaccess network device 203. The sending module 1702 may be configured toperform an operation of sending information to the first access networkdevice 202 by the second access network device 203. The receiving modulemay be configured to perform an operation of receiving information fromthe first access network device 202 by the second access network device203.

For a procedure in which the second access network device interacts withthe first access network device, refer to the procedure in which thesecond access network device 203 interacts with the first access networkdevice 202 in the procedure shown in FIG. 9 or FIG. 10. For content anda structure of a message sent or received by the second access networkdevice, also refer to the description of the procedure.

An optional implementation of the second access network device may beshown in FIG. 18. A processor 1801 may be configured to implement afunction of the processing module 1701. A transmitter 1802 may beconfigured to implement a function of the sending module 1702.Optionally, a receiver may further be included, and may be configured toimplement a function of the receiving module. In addition, the secondaccess network device may further include a memory, configured to storea program and data. The processor 1801 may perform processing andcontrol by invoking the program stored in the memory.

If the second access network device and the first access network devicecommunicate with each other by means of optical fiber transmission, thetransmitter 1802 may be an optical transmitter, and the receiver may bean optical receiver. If the second access network device and the firstaccess network device communicate with each other by means of microwavetransmission, the transmitter 1802 may be a microwave transmitter, andthe receiver may be a microwave receiver.

In addition, the second access network device may further include aradio frequency transceiver that communicates with the terminal device.

The transmitter 1802, the memory, and the receiver each may be directlyconnected to the processor 1801. Alternatively, the transmitter 1802,the memory, the receiver, and the processor 1801 each are connected to abus, and the components communicate with each other by using the bus.

Embodiment 9

FIG. 19 is a schematic structural diagram of a first access networkdevice according to Embodiment 9. As shown in FIG. 19, the first accessnetwork device includes:

a receiving module 1901, configured to receive a first air interfaceconfiguration message from a second access network device in a radioaccess network, where the first access network device and the secondaccess network device use different wireless communications standards,and the first air interface configuration message includes air interfaceconfiguration information of an air interface between a terminal deviceand the radio access network; and

a first sending module 1902, configured to send the first air interfaceconfiguration message to the terminal device, where

the air interface between the terminal device and the radio accessnetwork includes a first air interface and a second air interface; thefirst air interface includes a first air interface protocol layer and asecond air interface protocol layer, the first air interface protocollayer is between the terminal device and the first access networkdevice, the second air interface protocol layer is between the terminaldevice and the second access network device, and the second airinterface protocol layer is above the first air interface protocollayer; the second air interface is an air interface between the terminaldevice and the second access network device; and the first air interfaceconfiguration message is a message of an air interface protocol layerthat is included in the second air interface and that is used toconfigure an air interface.

The first access network device may further include a processing module,configured to perform processing and control operations of the firstaccess network device.

For another optional implementation of the first access network device,refer to implementation of the first access network device 202 inEmbodiment 3 or Embodiment 4. The processing module may be configured toperform processing and control operations of the first access networkdevice 202. The first sending module 1902 may be configured to performan operation of sending information to the terminal device 201 by thefirst access network device 202. The receiving module 1901 may beconfigured to perform an operation of receiving information from thesecond access network device 203 by the first access network device 202.

For a procedure in which the first access network device interacts withthe second access network device and the terminal device, refer to theprocedure in which the first access network device 202 interacts withthe second access network device 203 and the terminal device 201 in theprocedure shown in FIG. 9 or FIG. 10. For content and a structure of amessage sent or received by the first access network device, also referto the description of the procedure.

An optional implementation of the first access network device may beshown in FIG. 20. A first transmitter 2002 may be configured toimplement a function of the first sending module 1902. A receiver 2001may be configured to implement a function of the receiving module 1901.A processor may further be included, and may be configured to implementa function of the processing module. In addition, the first accessnetwork device may further include a memory, configured to store aprogram and data. The processor may perform processing and control byinvoking the program stored in the memory.

The first transmitter 2002 may be a radio frequency transmitter. If thefirst access network device and the second access network devicecommunicate with each other by means of optical fiber transmission, thereceiver 2001 may be an optical receiver. If the first access networkdevice and the second access network device communicate with each otherby means of microwave transmission, the receiver 2001 may be a microwavereceiver.

In addition, the first access network device may further include a radiofrequency receiver receiving a message and/or data that are/is sent bythe terminal device, and a second transmitter sending a message and/ordata to the second access network device. The second transmitter may bean optical transmitter, a microwave transmitter, or the like.

The first transmitter 2002, the memory, and the receiver 2001 each maybe directly connected to the processor. Alternatively, the firsttransmitter 2002, the memory, the receiver 2001, and the processor eachare connected to a bus, and the components communicate with each otherby using the bus.

Embodiment 10

FIG. 21 is a schematic structural diagram of a terminal device accordingto Embodiment 10. As shown in FIG. 21, the terminal device includes:

a receiving module 2101, configured to receive a first air interfaceconfiguration message from a first access network device, where thefirst air interface configuration message is from a second accessnetwork device, and is forwarded by the first access network device; thefirst access network device and the second access network device arelocated in a same radio access network, the first access network deviceand the second access network device use different wirelesscommunications standards; and the first air interface configurationmessage includes air interface configuration information of an airinterface between the terminal device and the radio access network; and

a processing module 2102, configured to obtain the air interfaceconfiguration information from the first air interface configurationmessage, and configure the air interface between the terminal device andthe radio access network according to the air interface configurationinformation, where

the air interface between the terminal device and the radio accessnetwork includes a first air interface and a second air interface; thefirst air interface includes a first air interface protocol layer and asecond air interface protocol layer, the first air interface protocollayer is between the terminal device and the first access networkdevice, the second air interface protocol layer is between the terminaldevice and the second access network device, and the second airinterface protocol layer is above the first air interface protocollayer; the second air interface is an air interface between the terminaldevice and the second access network device; and the first air interfaceconfiguration message is a message of an air interface protocol layerthat is included in the second air interface and that is used toconfigure an air interface.

The terminal device may further include a sending module, configured tosend a message and/or data to the first access network device and/or thesecond access network device.

For another optional implementation of the terminal device, refer toimplementation of the terminal device 201 in Embodiment 3 or Embodiment4. The processing module 2102 may be configured to perform processingand control operations of the terminal device 201. The sending modulemay be configured to perform an operation of sending information to thefirst access network device 202 or the second access network device 203by the terminal device 201. The receiving module 2101 may be configuredto perform an operation of receiving information from the second accessnetwork device 203 or the first access network device 202 by theterminal device 201.

For a procedure in which the terminal device interacts with the secondaccess network device and the first access network device, refer to theprocedure in which the terminal device 201 interacts with the secondaccess network device 203 and the first access network device 202 in theprocedure showgirl in FIG. 9 or FIG. 10. For content and a structure ofa message sent or received by the terminal device, also refer to thedescription of the procedure.

An optional implementation of the terminal device may be shown in FIG.22. A processor 2202 may be configured to implement a function of theprocessing module 2102. A receiver 2201 may be configured to implement afunction of the receiving module 2101. A transmitter may further beincluded, and may be configured to implement a function of the sendingmodule. In addition, the terminal device may further include a memory,configured to store a program and data. The processor 2202 may performprocessing and control by invoking the program stored in the memory.

The transmitter may be a radio frequency transmitter. The receiver 2201may be a radio frequency receiver.

The transmitter, the memory, and the receiver 2201 each may be directlyconnected to the processor 2202. Alternatively, the transmitter, thememory, the receiver 2201, and the processor 2202 each are connected toa bus, and the components communicate with each other by using the bus.

In conclusion, in this application, the second access network devicesends the first air interface configuration message to configure an airinterface between the terminal device and the radio access network, soas to provide, in a case in which the terminal device needs to access awireless communications system by using two access network devices ofdifferent standards, a solution for successfully establishing aconnection between the terminal device and the two radio access networkdevices.

It can be understood that, in the embodiments of this application, amanner of communication between the first access network device and thesecond access network device are not particularly limited. For example,the first access network device and the second access network device maycommunicate with each other by means of a microwave or an optical fiber.When the first access network device and the second access networkdevice communicate with each other by means of a microwave, both thefirst access network device and the second access network device areinternally provided with a microwave receiver and a microwavetransmitter, or a microwave transceiver. When the first access networkdevice and the second access network device communicate with each otherby means of an optical fiber, both the first access network device andthe second access network device are internally provided with an opticalreceiver and an optical transmitter, or an optical transceiver.

Persons skilled in the art should understand that the embodiments of thepresent disclosure may be provided as a method, a system, or a computerprogram product. Therefore, the present disclosure may use a form ofhardware only embodiments, software only embodiments, or embodimentswith a combination of software and hardware. Moreover, the presentdisclosure may use a form of a computer program product that isimplemented on one or more computer-usable storage media (including butnot limited to a disk memory, a CD-ROM, an optical memory, and the like)that include computer-usable program code.

The present disclosure is described with reference to the flowchartsand/or block diagrams of the method, the device (system), and thecomputer program product according to the embodiments of thisapplication, it should be understood that computer program instructionsmay be used to implement each process and/or each block in theflowcharts and/or the block diagrams and a combination of a processand/or a block in the flowcharts and/or the block diagrams. Thesecomputer program instructions may be provided for a general-purposecomputer, a dedicated computer, an embedded processor, or a processor ofany other programmable data processing device to generate a machine, sothat the instructions executed by a computer or a processor of any otherprogrammable data processing device generate an apparatus forimplementing a specific function in one or more processes in theflowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readablememory that can instruct the computer or any other programmable dataprocessing device to work in a specific manner, so that the instructionsstored in the computer readable memory generate an artifact thatincludes an instruction apparatus. The instruction apparatus implementsa specific function in one or more processes in the flowcharts and/or inone or more blocks in the block diagrams.

These computer program instructions may be loaded onto a computer oranother programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

Although some embodiments of the present disclosure have been described,persons skilled in the art can make changes and modifications to theseembodiments once they learn the basic inventive concept. Therefore, thefollowing claims are intended to be construed as covering theembodiments and all changes and modifications falling within the scopeof the present disclosure.

Obviously, persons skilled in the art can make various modifications andvariations to the embodiments of this application without departing fromthe scope of the embodiments of this application. The present disclosureis intended to cover these modifications and variations provided thatthey fall within the protection scope defined by the following claimsand their equivalent technologies.

What is claimed is:
 1. A method for a radio access network including afirst access network device and a second access network device usingdifferent wireless communications standards, the method comprising:determining, by the second access network device, air interfaceconfiguration information of an air interface of a terminal device forcommunications between the terminal device and the radio access network;and sending, by the second access network device, a first air interfaceconfiguration message comprising the air interface configurationinformation to the first access network device; wherein: a protocolstack of the air interface between the terminal device and the radioaccess network comprises a first air interface protocol layer and asecond air interface protocol layer; the first air interface protocollayer is for communications between the terminal device and the firstaccess network device; the second air interface protocol layer is forcommunications between the terminal device and the second access networkdevice; the second air interface protocol layer is above the first airinterface protocol layer; the second air interface protocol layerincludes an air interface protocol layer used to configure the airinterface; and the first air interface configuration message is amessage of the air interface protocol layer used to configure the airinterface.
 2. The method according to claim 1, further comprises:receiving a third air interface configuration message from the firstaccess network device before the determining the air interfaceconfiguration information; obtaining configuration information of thefirst air interface protocol layer from the third air interfaceconfiguration message; and wherein determining the air interfaceconfiguration information comprises: determining that the air interfaceconfiguration information comprises the configuration information of thefirst air interface protocol layer obtained from the third air interfaceconfiguration message.
 3. The method according to claim 1, wherein thesecond access network device is a Long term Evolution (LTE) systemaccess network device, and wherein the first access network device is afifth generation (5G) system access network device.
 4. The methodaccording to claim 1, wherein the second access network device is an LTEbase station, and wherein the air interface protocol layer used toconfigure the air interface is a radio resource control (RRC) layer. 5.The method according to claim 1, wherein the first air interfaceprotocol layer includes radio link control (RLC) layer, media accesscontrol (MAC) layer, and physical (PHY) layer, and wherein the secondair interface protocol layer includes packet data convergence protocol(PDCP) layer and radio resource control (RRC) layer.
 6. A method for aradio access network including a first access network device and asecond access network device using different wireless communicationsstandards, the method comprising: receiving, by the first access networkdevice, a first air interface configuration message from the secondaccess network device, wherein the first air interface configurationmessage comprises air interface configuration information of an airinterface of a terminal device for communications between the terminaldevice and the radio access network; and sending, by the first accessnetwork device, the first air interface configuration message to theterminal device; wherein: a protocol stack of the air interface betweenthe terminal device and the radio access network comprises a first airinterface protocol layer and a second air interface protocol layer; thefirst air interface protocol layer is for communications between theterminal device and the first access network device; the second airinterface protocol layer is for communications between the terminaldevice and the second access network device; the second air interfaceprotocol layer is above the first air interface protocol layer; thesecond air interface protocol layer includes an air interface protocollayer used to configure the air interface; and the first air interfaceconfiguration message is a message of the air interface protocol layerused to configure the air interface.
 7. The method according to claim 6,further comprises: sending a third air interface configuration messageto the second access network device, wherein the third air interfaceconfiguration message is for obtaining configuration information of thefirst air interface protocol layer.
 8. The method according to claim 6,wherein the second access network device is a Long term Evolution (LTE)system access network device, and wherein the first access networkdevice is a fifth generation (5G) system access network device.
 9. Themethod according to claim 6, wherein the second access network device isan LTE base station, and wherein the air interface protocol layer usedto configure the air interface is a radio resource control (RRC) layer.10. The method according to claim 6, wherein the first air interfaceprotocol layer includes radio link control (RLC) layer, media accesscontrol (MAC) layer, and physical (PHY) layer, and wherein the secondair interface protocol layer includes packet data convergence protocol(PDCP) layer and radio resource control (RRC) layer.
 11. A method,comprising: receiving, by a terminal device, a first air interfaceconfiguration message from a first access network device, wherein thefirst air interface configuration message is from a second accessnetwork device, and is forwarded by the first access network device,wherein the first access network device and the second access networkdevice are located in a same radio access network, wherein the firstaccess network device and the second access network device use differentwireless communications standards, and wherein the first air interfaceconfiguration message comprises air interface configuration informationof an air interface of the terminal device for communications betweenthe terminal device and the radio access network; and obtaining, by theterminal device, the air interface configuration information from thefirst air interface configuration message, and configuring the airinterface between the terminal device and the radio access networkaccording to the air interface configuration information; wherein: aprotocol stack of the air interface between the terminal device and theradio access network comprises a first air interface protocol layer anda second air interface protocol layer; the first air interface protocollayer is for communications between the terminal device and the firstaccess network device; the second air interface protocol layer is forcommunications between the terminal device and the second access networkdevice; the second air interface protocol layer is above the first airinterface protocol layer; the second air interface protocol layerincludes an air interface protocol layer used to configure the airinterface; and the first air interface configuration message is amessage of the air interface protocol layer used to configure the airinterface.
 12. The method according to claim 11, wherein the first airinterface protocol layer includes radio link control (RLC) layer, mediaaccess control (MAC) layer, and physical (PHY) layer, and wherein thesecond air interface protocol layer includes packet data convergenceprotocol (PDCP) layer and radio resource control (RRC) layer.
 13. Aradio access network, wherein the network comprises: a first accessnetwork device and a second access network device, wherein the firstaccess network device and the second access network device use differentwireless communications standards; wherein the second access networkdevice comprises: a non-transitory memory storage comprising secondinstructions; and a second hardware processor in communication with thenon-transitory memory storage, wherein the second hardware processorexecutes the second instructions to perform operations comprising:determining air interface configuration information of an air interfaceof a terminal device for communications between the terminal device andthe radio access network; sending a first air interface configurationmessage comprising the air interface configuration information to thefirst access network device; and the first access network device,comprises: a non-transitory memory storage comprising firstinstructions; and a first hardware processor in communication with thenon-transitory memory storage, wherein the first hardware processorexecutes the first instructions to perform operations comprising:receiving the first air interface configuration message from the secondaccess network device; sending the first air interface configurationmessage to the terminal device; wherein: a protocol stack of the airinterface between the terminal device and the radio access networkcomprises a first air interface protocol layer and a second airinterface protocol layer; the first air interface protocol layer is forcommunications between the terminal device and the first access networkdevice; the second air interface protocol layer is for communicationsbetween the terminal device and the second access network device; thesecond air interface protocol layer is above the first air interfaceprotocol layer; the second air interface protocol layer includes an airinterface protocol layer used to configure the air interface; and thefirst air interface configuration message is a message of the airinterface protocol layer used to configure the air interface.
 14. Theradio access network according to claim 13, wherein the first hardwareprocessor executes the first instructions to perform operationscomprising: sending a third air interface configuration message to thesecond access network device, wherein the third air interfaceconfiguration message is for obtaining configuration information of thefirst air interface protocol layer; and wherein the second hardwareprocessor executes the second instructions to perform operationscomprising: receiving the third air interface configuration message fromthe first access network device before the determining the air interfaceconfiguration information; obtaining configuration information of thefirst air interface protocol layer from the third air interfaceconfiguration message; and determining that the air interfaceconfiguration information comprises the configuration information of thefirst air interface protocol layer.
 15. The network according to claim13, wherein the second access network device is a Long term Evolution(LTE) system access network device, and wherein the first access networkdevice is a fifth generation (5G) system access network device.
 16. Thenetwork according to claim 13, wherein the second access network deviceis an LTE base station, and wherein the air interface protocol layerused to configure the air interface is a radio resource control (RRC)layer.
 17. The network according to claim 13, wherein the first airinterface protocol layer includes radio link control (RLC) layer, mediaaccess control (MAC) layer, and physical (PHY) layer, and wherein thesecond air interface protocol layer includes packet data convergenceprotocol (PDCP) layer and radio resource control (RRC) layer.